2012 GMC Sierra Owners Manual

case in the vehicle. Notice: Driving on clean, dry pavement in Four-Wheel Drive High or Four-Wheel Drive Low for an extended period of time may cause premature wear on the vehicle's powertrain. Do not drive on clean, dry pavement in Four-Wheel Drive High or Four-Wheel Drive Low for extended periods of time.

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While driving on clean dry pavement and during tight turns, you may experience vibration in the steering system. If the vehicle has StabiliTrak®, shifting into Four-Wheel Drive Low will turn Traction Control and StabiliTrak off. See StabiliTrak® System on page 9‑55. Front Axle The front axle engages and disengages automatically when you shift the transfer case. Some delay for the axle to engage or disengage is normal.

Driving and Operating

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Manual Transfer Case

A Four-Wheel Drive indicator light comes on when you shift into four-wheel drive and the front axle engages. See Four-Wheel-Drive Light on page 5‑26. Some delay between shifting and when the indicator light comes on is normal.

The transfer case shift lever is on the floor to the right of the driver. Use this lever to shift into and out of Four-Wheel Drive.

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Driving and Operating

Recommended Transfer Case Settings

Driving Conditions

Normal Severe Extreme

Vehicle in Tow*

Transfer Case Settings

4m

4n

2m

YES

YES

YES

YES

*See Recreational Vehicle Towing on page 10‑93 or Towing the Vehicle on page 10‑93.

Notice: Driving on clean, dry pavement in four-wheel drive for an extended period of time can cause premature wear on the vehicle's powertrain. Do not drive on clean, dry pavement in Four-Wheel Drive for extended periods of time.

4 n (Four-Wheel Drive Low): This setting also engages the front axle and delivers extra torque. You may never need Four-Wheel Drive Low. It sends maximum power to all four wheels. You might choose Four-Wheel Drive Low if you are driving off-road in deep sand, deep mud, deep snow, and while climbing or descending steep hills.

If the vehicle has StabiliTrak®, shifting into Four-Wheel Drive Low will turn Traction Control and StabiliTrak off. See StabiliTrak® System on page 9‑55.

A parking brake symbol is located next to the N (Neutral) symbol as a reminder to set the parking brake before shifting the transfer case into N (Neutral).

{ WARNING

Shifting the transfer case to N (Neutral) can cause the vehicle to roll even if the transmission is in P (Park). You or someone else could be seriously injured. Be sure to set the parking brake

(Continued)

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Driving and Operating

9-43

WARNING (Continued)

before placing the transfer case in N (Neutral). See Parking Brake on page 9‑54.

N (Neutral): Shift to this setting only when the vehicle needs to be towed. See Recreational Vehicle Towing on page 10‑93 or Towing the Vehicle on page 10‑93. 2 m (Two-Wheel Drive High): This setting is used for driving in most street and highway situations. The front axle is not engaged in two-wheel drive. This setting also provides the best fuel economy. 4 m (Four-Wheel Drive High): Use this setting when you need extra traction, such as on snowy or icy roads or in most off-road situations. This setting also engages the front axle to help drive your vehicle. This is the best setting to use when plowing snow.

You can shift from Two-Wheel Drive High to Four-Wheel Drive High or Four-Wheel Drive High to Two-Wheel Drive High while the vehicle is moving. In extremely cold weather, it may be necessary to stop or slow the vehicle to shift into Four-Wheel Drive High.

When Using the Manual Transfer Case . Shifts into or out of Four-Wheel Drive Low or N (Neutral) should be made using quick motions to avoid excessive gear grinding. Shifting slowly may make it more difficult to shift.

. You may notice that it is harder to shift when the vehicle is cold. After the vehicle warms up the shifting will return to normal. . While in Four-Wheel High or

Four-Wheel Drive Low you may experience reduced fuel economy.

. Avoid driving in Four-Wheel

Drive on clean, dry pavement. It may cause your tires to wear faster, make the transfer case harder to shift, and run noisier. If the transfer case shifter is in the N (Neutral) position and you have difficulty reaching the selected transfer case mode, with the engine running, shift the transmission momentarily to D (Drive) and then back to N (Neutral). This will realign the gear teeth in the transfer case and allow you to complete the shift.

Shifting from Two-Wheel Drive High to Four-Wheel Drive High . Shifts between Two-Wheel Drive High and Four-Wheel Drive High can be made at any vehicle speed.

. Shift the transfer case lever in

one continuous motion into either the Four-Wheel Drive High or Two-Wheel Drive High position.

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Driving and Operating

. Shifting from Two-Wheel Drive High to Four-Wheel Drive High while the vehicle is in motion may require that moderate force be applied to the shift lever for a few seconds before Four-Wheel Drive High can be engaged, especially in cold weather. In extremely cold weather, it may be necessary to slow or stop the vehicle to shift into Four-Wheel Drive High.

. While in Four-Wheel Drive High, the vehicle can be driven at any posted legal speed limit.

Shifting In or Out of Four-Wheel Drive Low Notice: Shifting the transfer case into Four-Wheel-Drive Low while moving at speeds faster than 5 km/h (3 mph) may cause premature wear to the transfer case, and may cause the gears to grind. To avoid causing premature wear, and grinding the gears, do not shift the transfer

case into Four-Wheel-Drive Low while the vehicle is moving faster than 5 km/h (3 mph). . Shifting into Four-Wheel Drive

Low should be done, if possible, with the vehicle at a slight roll, 5 km/h (3 mph) or less.

. Shift the transmission into

N (Neutral).

{ WARNING

Shifting the transfer case to N (Neutral) can cause the vehicle to roll even if the transmission is in P (Park). You or someone else could be seriously injured. Be sure to set the parking brake before placing the transfer case in N (Neutral). See Parking Brake on page 9‑54.

. Shifting into Four-Wheel Drive Low with the vehicle at a stop may be more difficult. You may be unable to complete the shift to Four-Wheel Drive Low, and

the transfer case will end up in N (Neutral). This is normal, and is a function of the gear teeth aligning in the transfer case. When this happens, make sure the engine is on, shift the transmission momentarily to D (Drive) and back to N (Neutral), and then complete the transfer case shift.

. Shift the transfer case shift lever

in one continuous motion into the Four-Wheel Drive Low position.

. When in Four-Wheel Drive

Low do not drive faster than 72 km/h (45 mph). This will reduce wear and extend the life of your transfer case.

Shifting In or Out of Neutral 1. With the vehicle running and the engine at an idle, set the parking brake.

2. Place the transmission into

N (Neutral).

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Shift the transfer case in one continuous motion into or out of the N (Neutral) position. Electronic Transfer Case

The transfer case knob is located next to the steering column. Use the dial to shift into and out of four-wheel drive.

Driving and Operating

9-45

Recommended Transfer Case Settings

Driving Conditions

Normal Severe Extreme

Vehicle in Tow*

Transfer Case Settings

4m

4n

2m

YES

YES

YES

YES

*See Recreational Vehicle Towing on page 10‑93 or Towing the Vehicle on page 10‑93.

You can choose among four driving settings: Indicator lights in the dial show which setting you are in. The indicator lights will come on briefly when you turn on the ignition and one will stay on. If the lights do not come on, you should take the vehicle to your dealer for service. An indicator light flashes while shifting the transfer case and remains illuminated when the shift is

complete. If for some reason the transfer case cannot make a requested shift, it will return to the last chosen setting. 2 m (Two-Wheel Drive High): This setting is used for driving in most street and highway situations. The front axle is not engaged in Two-Wheel Drive. This setting also provides the best fuel economy.

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Driving and Operating

4 m (Four-Wheel Drive High): Use the Four-Wheel Drive High position when extra traction is needed, such as on snowy or icy roads or in most off-road situations. This setting also engages the front axle to help drive the vehicle. This is the best setting to use when plowing snow. 4 n (Four-Wheel Drive Low): This setting also engages the front axle and delivers extra torque. You may never need this setting. It sends maximum power to all four wheels. You might choose Four-Wheel Drive Low while driving off-road in deep sand, deep mud, deep snow, and while climbing or descending steep hills. If the vehicle has StabiliTrak®, shifting into Four-Wheel Drive Low will turn Traction Control and StabiliTrak off. See StabiliTrak® System on page 9‑55.

{ WARNING

Shifting the transfer case to N (Neutral) can cause the vehicle to roll even if the transmission is in P (Park). You or someone else could be seriously injured. Be sure to set the parking brake before placing the transfer case in N (Neutral). See Parking Brake on page 9‑54.

N (Neutral): Shift the vehicle's transfer case to N (Neutral) only when towing the vehicle. See Recreational Vehicle Towing on page 10‑93 or Towing the Vehicle on page 10‑93 for more information. If the SERVICE 4 WHEEL DRIVE message stays on, you should take the vehicle to your dealer for service. See “SERVICE 4 WHEEL DRIVE” under Transmission Messages on page 5‑46.

Shifting Into Two-Wheel Drive High Turn the knob to the Two-Wheel Drive High position. This can be done at any speed, except when shifting from Four-Wheel Drive Low. See “Shifting Out of Four-Wheel Drive Low” for more information.

Shifting Into Four-Wheel Drive Low When Four-Wheel Drive Low is engaged, vehicle speed should be kept below 72 km/h (45 mph). Extended high-speed operation in Four-Wheel Drive Low may damage or shorten the life of the drivetrain. To shift to the Four-Wheel Drive Low position, the ignition must be in ON/RUN and the vehicle must be stopped or moving less than 5 km/h (3 mph) with the transmission in N (Neutral). The preferred method for shifting into Four-Wheel Drive Low is to have the vehicle moving 1.6 to 3.2 km/h (1 to 2 mph). Turn the knob to the Four-Wheel Drive Low position. You must wait for the

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Four-Wheel Drive Low indicator light to stop flashing and remain on before shifting the transmission in gear. Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. It is typical for the vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from transfer case N (Neutral) with the engine running. If the knob is turned to the Four-Wheel Drive Low position when the vehicle is in gear and/or moving more than 5 km/h (3 mph), the Four-Wheel Drive Low indicator light will flash for 30 seconds and not complete the shift.

After 30 seconds the transfer case will shift to Four-Wheel Drive High mode.

Shifting Out of Four-Wheel Drive Low To shift from Four-Wheel Drive Low to Four-Wheel Drive High, or Two-Wheel Drive High, the vehicle must be stopped or moving less than 5 km/h (3 mph) with the transmission in N (Neutral) and the ignition in ON/RUN. The preferred method for shifting out of Four-Wheel Drive Low is to have the vehicle moving 1.6 to 3.2 km/h (1 to 2 mph). Turn the knob to the Four-Wheel Drive High or Two-Wheel Drive High position. You must wait for the Four-Wheel Drive High or Two-Wheel Drive High indicator light to stop flashing and remain on before shifting the transmission into gear.

Driving and Operating

9-47

Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. It is typical for the vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from transfer case N (Neutral) with the engine running. If the knob is turned to the Four-Wheel Drive High, or Two-Wheel Drive High switch position when the vehicle is in gear and/or moving more than 5 km/h (3 mph), the Four-Wheel Drive High, AUTO, or Two-Wheel Drive High indicator light will flash for 30 seconds but will not complete the shift.

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9-48

Driving and Operating

Shifting into Neutral To shift the transfer case to N (Neutral) do the following: 1. Make sure the vehicle is parked

so that it will not roll.

2. Set the parking brake and press

and hold the regular brake pedal. See Parking Brake on page 9‑54 for more information.

3. Start the vehicle or turn the

ignition to ON/RUN.

4. Shift the transmission to

N (Neutral).

5. Shift the transfer case to

Two-Wheel Drive High.

6. Turn the transfer case dial

clockwise to N (Neutral) until it stops and hold it there until the Neutral light starts blinking. This will take at least 10 seconds. Then slowly release the dial to the four low position. The N (Neutral) light will come on when the transfer case shift to N (Neutral) is complete.

7.

If the engine is running, verify that the transfer case is in N (Neutral) by shifting the transmission to R (Reverse) for one second, then shift the transmission to D (Drive) for one second.

8. Turn the ignition to ACC/

ACCESSORY, which will turn the engine off.

9. Place the transmission shift

lever in P (Park).

10. Release the parking brake prior

to moving the vehicle.

11. Turn the ignition to LOCK/OFF.

Shifting Out of Neutral To shift the transfer case out of N (Neutral) do the following: 1. Set the parking brake and apply

the regular brake pedal.

2. Turn the ignition to ON/RUN with

the engine off, and shift the transmission to N (Neutral).

3. Turn the transfer case dial to

Two-Wheel Drive High.

After the transfer case has shifted out of N (Neutral), the N (Neutral) light will go out.

4. Release the parking brake prior

to moving the vehicle.

Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. 5. Start the engine and shift the

transmission to the desired position.

Excessively shifting the transfer case into or out of the different modes may cause the transfer case to enter the shift protection mode. This will protect the transfer case from possible damage and will only allow the transfer case to respond to one shift per 10 seconds. The transfer case may stay in this mode for up to three minutes.

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Automatic Transfer Case

The transfer case knob is located next to the steering column. Use the dial to shift into and out of Four-Wheel Drive. You can choose among five driving settings: Indicator lights in the dial show which setting you are in. The indicator lights will come on briefly when you turn on the ignition and

Driving and Operating

9-49

one will stay on. If the lights do not come on, you should take the vehicle to your dealer for service. An indicator light will flash while shifting the transfer case. It will remain illuminated when the shift is complete. If for some reason the transfer case cannot make a requested shift, it will return to the last chosen setting. 2 m (Two-Wheel Drive High): This setting is used for driving in most street and highway situations. The front axle is not engaged in Two-Wheel Drive. This setting also provides the best fuel economy. AUTO (Automatic Four-Wheel Drive): This setting is ideal for use when road surface traction conditions are variable. When driving the vehicle in AUTO, the front axle is engaged, but the vehicle's power is sent only to the

front and rear wheels automatically based on driving conditions. Driving in this mode results in slightly lower fuel economy than Two-Wheel Drive High. 4 m (Four-Wheel Drive High): Use the Four-Wheel Drive High position when extra traction is needed, such as on snowy or icy roads or in most off-road situations. This setting also engages the front axle to help drive the vehicle. This is the best setting to use when plowing snow. 4 n (Four-Wheel Drive Low): This setting also engages the front axle and delivers extra torque. You may never need this setting. It sends maximum power to all four wheels. You might choose Four-Wheel Drive Low if you are driving off-road in deep sand, deep mud, deep snow, and while climbing or descending steep hills.

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Driving and Operating

If the vehicle has StabiliTrak®, shifting into Four-Wheel Drive Low will turn Traction Control and StabiliTrak off. See StabiliTrak® System on page 9‑55.

{ WARNING

Shifting the transfer case to N (Neutral) can cause the vehicle to roll even if the transmission is in P (Park). You or someone else could be seriously injured. Be sure to set the parking brake before placing the transfer case in N (Neutral). See Parking Brake on page 9‑54.

N (Neutral): Shift the vehicle's transfer case to N (Neutral) only when towing the vehicle. See Recreational Vehicle Towing on page 10‑93 or Towing the Vehicle on page 10‑93 for more information.

If the SERVICE 4 WHEEL DRIVE message stays on, you should take the vehicle to your dealer for service. See “SERVICE 4 WHEEL DRIVE” under Transmission Messages on page 5‑46.

Shifting Into Four-Wheel Drive High or AUTO (Automatic Four-Wheel Drive) Turn the knob to the Four-Wheel Drive High or AUTO position. This can be done at any speed, except when shifting from Four-Wheel Drive Low. The indicator light will flash while shifting. It will remain on when the shift is completed.

Shifting Into Two-Wheel Drive High Turn the knob to the Two-Wheel Drive High position. This can be done at any speed, except when shifting from Four-Wheel Drive Low. The indicator light will flash while shifting. It will remain on when the shift is completed.

Shifting Into Four-Wheel Drive Low When Four-Wheel Drive Low is engaged, vehicle speed should be kept below 72 km/h (45 mph). Extended high-speed operation in Four-Wheel Drive Low may damage or shorten the life of the drivetrain. To shift to the Four-Wheel Drive Low position, the ignition must be in ON/RUN and the vehicle must be stopped or moving less than 5 km/h (3 mph) with the transmission in N (Neutral). The preferred method for shifting into Four-Wheel Drive Low is to have the vehicle moving 1.6 to 3.2 km/h (1 to 2 mph). Turn the knob to the Four-Wheel Drive Low position. You must wait for the Four-Wheel Drive Low indicator light to stop flashing and remain on before shifting the transmission into gear.

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Driving and Operating

9-51

Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. It is typical for the vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from N (Neutral) with the engine running. If the knob is turned to the Four-Wheel Drive Low position when the vehicle is in gear and/or moving more than 5 km/h (3 mph), the Four-Wheel Drive Low indicator light will flash for 30 seconds and not complete the shift. After 30 seconds the transfer case will shift to Four-Wheel Drive High mode.

Shifting Out of Four-Wheel Drive Low To shift from Four-Wheel Drive Low to Four-Wheel Drive High, AUTO or Two-Wheel Drive High, the vehicle must be stopped or moving less than 5 km/h (3 mph) with the transmission in N (Neutral) and the ignition in ON/RUN. The preferred method for shifting out of Four-Wheel Drive Low is to have the vehicle moving 1.6 to 3.2 km/h (1 to 2 mph). Turn the knob to the Four-Wheel Drive High, AUTO or Two-Wheel Drive High position. You must wait for the Four-Wheel Drive High, AUTO or Two-Wheel Drive High indicator light to stop flashing and remain on before shifting the transmission into gear. Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid

damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. It is typical for the vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Drive Low and Four-Wheel Drive High ranges or from N (Neutral) with the engine running. If the knob is turned to the Four-Wheel Drive High, AUTO, or Two-Wheel Drive High switch position when the vehicle is in gear and/or moving more than 5 km/h (3 mph), the Four-Wheel Drive High, AUTO or Two-Wheel Drive High indicator light will flash for 30 seconds but will not complete the shift.

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9-52

Driving and Operating

Shifting into Neutral To shift the transfer case to N (Neutral) do the following: 1. Make sure the vehicle is parked

so that it will not roll.

2. Set the parking brake and apply

the regular brake pedal. See Parking Brake on page 9‑54 for more information.

3. Start the vehicle or turn the

ignition in ON/RUN.

4. Put the transmission in

N (Neutral).

5. Shift the transfer case to

Two-Wheel Drive High.

6. Turn the transfer case dial

clockwise to N (Neutral) until it stops and hold it there until the N (Neutral) light starts blinking. This will take at least 10 seconds. Then slowly release the dial to the four low position. The N (Neutral) light will come on when the transfer case shift to N (Neutral) is complete.

7.

If the engine is running, make sure that the transfer case is in N (Neutral) by shifting the transmission to R (Reverse) for one second, then shift the transmission to D (Drive) for one second.

8. Turn the ignition to ACC/

ACCESSORY, which will turn the engine off.

9. Place the transmission shift

lever in P (Park).

10. Release the parking brake prior

to moving the vehicle.

11. Turn the ignition to LOCK/OFF.

Shifting Out of Neutral To shift out of N (Neutral) do the following: 1. Set the parking brake and apply

the regular brake pedal.

2. Turn the ignition to ON/RUN with

the engine off, and shift the transmission to N (Neutral).

3. Turn the transfer case dial to Two-Wheel Drive High, Four-Wheel Drive High, or AUTO. After the transfer case has shifted out of N (Neutral), the N (Neutral) light will go out.

4. Release the parking brake prior

to moving the vehicle.

Notice: Shifting the transmission into gear before the requested mode indicator light has stopped flashing could damage the transfer case. To help avoid damaging the vehicle, always wait for the mode indicator lights to stop flashing before shifting the transmission into gear. 5. Start the engine and shift the

transmission to the desired position.

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Driving and Operating

9-53

Brakes

Antilock Brake System (ABS) This vehicle has the Antilock Brake System (ABS), an advanced electronic braking system that helps prevent a braking skid. When the engine is started and the vehicle begins to drive away, ABS checks itself. A momentary motor or clicking noise might be heard while this test is going on, and it might even be noticed that the brake pedal moves a little. This is normal.

If there is a problem with ABS, this warning light stays on. See Antilock Brake System (ABS) Warning Light on page 5‑26.

If driving safely on a wet road and it becomes necessary to slam on the brakes and continue braking to avoid a sudden obstacle, a computer senses that the wheels are slowing down. If one of the wheels is about to stop rolling, the computer will separately work the brakes at each wheel. ABS can change the brake pressure to each wheel, as required, faster than any driver could. This can help the driver steer around the obstacle while braking hard. As the brakes are applied, the computer keeps receiving updates on wheel speed and controls braking pressure accordingly. Remember: ABS does not change the time needed to get a foot up to the brake pedal or always decrease stopping distance. If you get too close to the vehicle in front of you, there will not be enough time to apply the brakes if that vehicle

suddenly slows or stops. Always leave enough room up ahead to stop, even with ABS. Using ABS Do not pump the brakes. Just hold the brake pedal down firmly and let ABS work. You might hear the ABS pump or motor operating and feel the brake pedal pulsate, but this is normal. Braking in Emergencies ABS allows the driver to steer and brake at the same time. In many emergencies, steering can help more than even the very best braking.

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Driving and Operating

Parking Brake

Set the parking brake by holding the regular brake pedal down, then pushing down the parking brake pedal. If the ignition is on, the brake system warning light will come on. See Brake System Warning Light on page 5‑25. Notice: Driving with the parking brake on can overheat the brake system and cause premature wear or damage to brake system parts. Make sure that the parking

brake is fully released and the brake warning light is off before driving. To release the parking brake, hold the regular brake pedal down, then push down momentarily on the parking brake pedal until you feel the pedal release. Slowly pull your foot up off the parking brake pedal. If the parking brake is not released when you begin to drive, the brake system warning light will flash and a chime will sound warning you that the parking brake is still on. If you are towing a trailer and are parking on a hill, see Driving Characteristics and Towing Tips on page 9‑74.

Brake Assist If this vehicle has StabiliTrak®, it also has a Brake Assist feature designed to assist the driver in stopping or decreasing vehicle speed in emergency driving conditions. This feature uses the stability system hydraulic brake

control module to supplement the power brake system under conditions where the driver has quickly and forcefully applied the brake pedal in an attempt to quickly stop or slow down the vehicle. The stability system hydraulic brake control module increases brake pressure at each corner of the vehicle until the ABS activates. Minor brake pedal pulsation or pedal movement during this time is normal and the driver should continue to apply the brake pedal as the driving situation dictates The Brake Assist feature will automatically disengage when the brake pedal is released or brake pedal pressure is quickly decreased.

Hill Start Assist (HSA) Non‐hybrid vehicles with StabiliTrak have a Hill Start Assist (HSA) feature, which may be useful when the vehicle is stopped on a grade.

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Driving and Operating

9-55

This feature is designed to prevent the vehicle from rolling, either forward or rearward, during vehicle drive off. After the driver completely stops and holds the vehicle in a complete standstill on a grade, HSA will be automatically activated. During the transition period between when the driver releases the brake pedal and starts to accelerate to drive off on a grade, HSA holds the braking pressure for a maximum of two seconds to ensure that there is no rolling. The brakes will automatically release when the accelerator pedal is applied within the two‐second window. If the vehicle is equipped with the Integrated Trailer Brake Control (ITBC) system, HSA may also apply the trailer brakes. It will not activate if the vehicle is in a drive gear and facing downhill or if the vehicle is facing uphill and in R (Reverse). There may be situations on minor hills (less than 5% grade) with a loaded vehicle or while pulling a trailer where HSA will not activate.

Ride Control Systems

StabiliTrak® System The vehicle has a vehicle stability enhancement system called StabiliTrak. It is an advanced computer-controlled system that assists the driver with directional control of the vehicle in difficult driving conditions. StabiliTrak activates when the computer senses a discrepancy between the intended path and the direction the vehicle is actually traveling. StabiliTrak selectively applies braking pressure at any one of the vehicle's brakes to assist the driver with keeping the vehicle on the intended path. StabiliTrak is on automatically whenever the vehicle is started. To assist with directional control of the vehicle, the system should always be left on. Trailer Sway Control (TSC) is also on automatically when

the vehicle is started. See Trailer Sway Control (TSC) on page 9‑105
for more information. When the vehicle is started and begins to move, the system performs several diagnostic checks to insure there are no problems. The system may be heard or felt while it is working. This is normal and does not mean there is a problem with the vehicle. The system should initialize before the vehicle reaches 32 km/h (20 mph). In some cases, it may take approximately 3.2 km (2 mi) of driving before the system initializes. If cruise control is being used when StabiliTrak activates, the cruise control automatically disengages. The cruise control can be re-engaged when road conditions allow. See Cruise Control on page 9‑58. If the system fails to turn on or activate, the StabiliTrak light along with a message will be displayed on the Driver Information Center (DIC).

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Driving and Operating

If a DIC message appears, make sure the StabiliTrak system has not been turned off using the Traction Control System (TCS)/StabiliTrak button. Then turn the vehicle off, wait 15 seconds, and then turn it back on again to reset the system. If any of the messages still appear on the DIC, the vehicle should be taken in for service. For more information on the DIC messages, see Ride Control System Messages on page 5‑44.

The TCS/StabiliTrak button is located on the instrument panel. The traction control part of StabiliTrak can be turned off by pressing and releasing the TCS/ StabiliTrak button if both systems (traction control and StabiliTrak) were previously on.

The StabiliTrak light will flash on the instrument panel cluster when the system or the TSC feature is both on and activated. The system may be heard or felt while it is working; this is normal.

To disable both TCS and StabiliTrak, press and hold the TCS/StabiliTrak button until the StabiliTrak OFF light illuminates and

the appropriate DIC message displays. This will also disable the TSC feature. Traction control and StabiliTrak can be turned on by pressing and releasing the TCS/StabiliTrak button if they are not automatically shut off for any other reason. This will also enable the TSC feature. When the TCS or StabiliTrak system is turned off, the StabiliTrak light and the appropriate message will be displayed on the DIC to warn the driver. The vehicle will still have brake-traction control when traction control is off, but will not be able to use the engine speed management system. See “Traction Control Operation” next for more information. When the TCS has been turned off, system noises may still be heard as a result of the brake-traction control coming on.

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It is recommended to leave the system on for normal driving conditions, but it may be necessary to turn the system off if the vehicle is stuck in sand, mud, ice or snow, and you want to “rock” the vehicle to attempt to free it. It may also be necessary to turn off the system when driving in extreme off-road conditions where high wheel spin is required. See If the Vehicle Is Stuck on page 9‑15. When the transfer case is in 4LO, the stability system is automatically disabled, the StabiliTrak light comes on, and the appropriate message will appear on the DIC. Both traction control and StabiliTrak are automatically disabled in this condition. Traction Control Operation The TCS is part of the StabiliTrak system. Traction control limits wheel spin by reducing engine power to the wheels (engine speed management) and by applying

brakes to each individual wheel (brake-traction control) as necessary. The TCS is enabled automatically when the vehicle is started. It will activate and the StabiliTrak light will flash if it senses that any of the wheels are spinning or beginning to lose traction while driving. If traction control is turned off, only the brake-traction control portion of traction control will work. The engine speed management will be disabled. In this mode, engine power is not reduced automatically and the driven wheels can spin more freely. This can cause the brake-traction control to activate constantly. Notice: If the wheel(s) of one axle is allowed to spin excessively while the StabiliTrak®, ABS, brake warning lights, and any relevant DIC messages are displayed, the transfer case could be damaged. The repairs would not be covered by the vehicle warranty. Reduce engine power and do not spin the

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wheel(s) excessively while these lights and messages are displayed. The TCS may activate on dry or rough roads or under conditions such as heavy acceleration while turning or abrupt upshifts/downshifts of the transmission. When this happens, a reduction in acceleration may be noticed, or a noise or vibration may be heard. This is normal. If cruise control is being used when the system activates, the StabiliTrak light will flash and cruise control will automatically disengage. Cruise control may be reengaged when road conditions allow. See Cruise Control on page 9‑58. StabiliTrak may also turn off automatically if it determines that a problem exists with the system. If the problem does not clear itself after restarting the vehicle, see your dealer for service.

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Driving and Operating

Non-hybrid vehicles with StabiliTrak have a Trailer Sway Control (TSC) feature. See Trailer Sway Control (TSC) on page 9‑105. Non-hybrid vehicles with StabiliTrak have a Hill Start Assist (HSA) feature. See Hill Start Assist (HSA) on page 9‑54. Adding non‐dealer accessories can affect the vehicle's performance. See Accessories and Modifications on page 10‑3.

Locking Rear Axle Vehicles with a locking rear axle can give more traction on snow, mud, ice, sand, or gravel. It works like a standard axle most of the time, but when traction is low, this feature will allow the rear wheel with the most traction to move the vehicle.

Cruise Control

{ WARNING

Cruise control can be dangerous where you cannot drive safely at a steady speed. So, do not use the cruise control on winding roads or in heavy traffic. Cruise control can be dangerous on slippery roads. On such roads, fast changes in tire traction can cause excessive wheel slip, and you could lose control. Do not use cruise control on slippery roads.

For vehicles with cruise control, a speed of about 40 km/h (25 mph) or more can be maintained without keeping your foot on the accelerator. Cruise control does not work at speeds below about 40 km/h (25 mph).

When the brakes are applied, cruise control is turned off. For vehicles with an Allison or Hydra‐Matic 6‐speed automatic transmission, see “Grade Braking” under Tow/Haul Mode on page 9‑39
for an explanation of how cruise control interacts with the Range Selection Mode, tow/haul and grade braking systems. For vehicles with the StabiliTrak system that begins to limit wheel spin while you are using cruise control, the cruise control will automatically disengage. See StabiliTrak® System on page 9‑55. When road conditions allow the cruise control to be safely used again, it can be turned back on.

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[ (Cancel): Press to disengage cruise control without erasing the set speed from memory.

Setting Cruise Control If the cruise button is on when not in use, it could get bumped and go into cruise when not desired. Keep the cruise control switch off when cruise is not being used. The cruise control light on the instrument panel cluster will come on after the cruise control has been set to the desired speed. 1. Press I. 2. Get up to the desired speed. 3. Press the SET− button located

on the steering wheel and release it.

4. Take your foot off the

accelerator.

Resuming a Set Speed If the cruise control is set at a desired speed and then the brakes are applied, the cruise control is disengaged without erasing the set speed from memory. Once the vehicle speed reaches about 40 km/h (25 mph) or more, press the +RES button on the steering wheel. The vehicle returns to the previous set speed and stays there.

Increasing Speed While Using Cruise Control If the cruise control system is already activated, . Press and hold the +RES button

on the steering wheel until the desired speed is reached, then release it. To increase vehicle speed in small amounts, press the +RES button. Each time this is done, the vehicle goes about 1.6 km/h (1 mph) faster.

I (On/Off): Press to turn the system on or off. The indicator light is on when cruise control is on and turns off when cruise control is off. + RES (Resume/Accelerate): Press briefly to resume to a previously set speed, or press and hold to accelerate. SET − (Set/Coast): Press to set the speed and activate cruise control or make the vehicle decelerate.

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Driving and Operating

Reducing Speed While Using Cruise Control If the cruise control system is already activated, . Press and hold the SET– button

on the steering wheel until the desired lower speed is reached, then release it. To slow down in small amounts, press the SET– button on the steering wheel briefly. Each time this is done, the vehicle goes about 1.6 km/h (1 mph) slower.

Passing Another Vehicle While Using Cruise Control Use the accelerator pedal to increase the vehicle speed. When you take your foot off the pedal, the vehicle will slow down to the previous set cruise speed.

Using Cruise Control on Hills How well the cruise control works on hills depends on the vehicle speed, the load, and the steepness of the hills. When going up steep

hills, pressing the accelerator pedal may be necessary to maintain vehicle speed. While going downhill: . Vehicles with a four speed

automatic transmission may need to have the brakes applied or the transmission shifted to a lower gear to keep the speed down.

. Vehicles with a six speed

automatic transmission have a Cruise Grade Braking feature that may automatically shift to a lower gear to keep the speed down. It may be necessary to apply the brake or manually shift the transmission to a lower gear. The vehicle may shift to a higher gear when grade braking assistance is no longer required. Cruise Grade Braking is not available while in Range Selection Mode. This feature is

active when the exhaust brake is enabled (if equipped). See "Range Selection Mode" under Manual Mode on page 9‑38. When the brakes are manually applied the cruise control is disengaged.

Ending Cruise Control There are three ways to end cruise control:

To disengage cruise control; step lightly on the brake pedal.

. Press [ on the steering wheel.

To turn off the cruise control, press I on the steering wheel.

Erasing Speed Memory The cruise control set speed is erased from memory by pressing I or if the ignition is turned off.

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Object Detection Systems

Ultrasonic Parking Assist If available, the Ultrasonic Rear Parking Assist (URPA) system assists the driver with parking and avoiding objects while in R (Reverse). URPA operates at speeds less than 8 km/h (5 mph). The sensors on the rear bumper detect objects up to 2.5 m (8 ft) behind the vehicle, and at least 25 cm (10 in) off the ground. { WARNING

The URPA system does not detect pedestrians, bicyclists, animals, or objects below the bumper or that are too close or too far from the vehicle. To prevent injury, death, or vehicle damage, even with URPA, always (Continued)

WARNING (Continued)

check the area around the vehicle and check all mirrors before backing.

How the System Works URPA comes on automatically when the shift lever is moved into R (Reverse). A single tone sounds to indicate the system is working. URPA operates only at speeds less than 8 km/h (5 mph). An obstacle is indicated by audible beeps. The interval between the beeps becomes shorter as the vehicle gets closer to the obstacle. When the distance is less than 30 cm (12 in) the beeping is a continuous tone for five seconds. To be detected, objects must be at least 25 cm (10 in) off the ground and below tailgate level. Objects must also be within 2.5 m (8 ft) from

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the rear bumper. This distance may be less during warmer or humid weather. Turning the System On and Off The URPA system can be turned on and off using the rear park aid disable button located next to the radio.

The indicator light comes on when the system is disabled and turns off when the system is on. When the system is off, PARK ASSIST OFF displays on the Driver Information Center (DIC). The message disappears after a short period of time.

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Driving and Operating

URPA defaults to the on setting each time the vehicle is started. Notice: If you use URPA while the tailgate is lowered, it may not detect an object behind your vehicle, and you might back into the object and damage your vehicle. Always verify the tailgate is closed when using URPA or turn off URPA when driving with the tailgate lowered. When the System Does Not Seem to Work Properly The following messages may be displayed on the DIC: SERVICE PARK ASSIST: message occurs, take the vehicle to your dealer to repair the system.

If this

PARK ASST BLOCKED SEE OWNERS MANUAL: This message can occur under the following conditions:

The ultrasonic sensors are not clean. Keep the vehicle's rear bumper free of mud, dirt, snow, ice, and slush. For cleaning instructions, see Exterior Care on page 10‑98. The park assist sensors are covered by frost or ice. Frost or ice can form around and behind the sensors and may not always be seen; this can occur after washing the vehicle in cold weather. The message may not clear until the frost or ice has melted.

. A trailer was attached to the

vehicle, or an object was hanging out of the tailgate during the last drive cycle. Once the object is removed and the tailgate is raised, URPA will return to normal operation.

. A tow bar is attached to the

vehicle. The bumper is damaged. Take the vehicle to your dealer to repair the system.

. Other conditions, such as

vibrations from a jackhammer or the compression of air brakes on a very large truck, are affecting system performance.

Rear Vision Camera (RVC) If available, the Rear Vision Camera (RVC) system displays part of the scene behind the vehicle. { WARNING

The RVC system does not display pedestrians, bicyclists, animals, or any other object located outside the camera's field of view, below the bumper, or under the vehicle. Do not back the vehicle

(Continued)

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WARNING (Continued)

using only the RVC screen, such as during longer, higher speed backing maneuvers, or where there could be cross-traffic. Perceived distances may be different from actual distances. Failure to use proper care before backing may result in injury, death, or vehicle damage. Always check behind and around the vehicle before backing.

Vehicles without Navigation System The RVC system displays a view of the area behind the vehicle. When the vehicle is on and shifted into R (Reverse) the video image appears on the inside rearview mirror. The video image disappears after the vehicle is shifted out of R (Reverse).

Turning the RVC System On or Off To turn off the RVC system, press and hold z , located on the inside rearview mirror, until the left indicator light turns off. The RVC display is now disabled. To turn the RVC system on, press and hold z until the left indicator light comes on. The RVC system display will appear in the mirror. Vehicles with Navigation System The RVC system is designed to help the driver when backing up by displaying a view of the area behind the vehicle. When the vehicle is shifted into R (Reverse), the video image appears on the navigation screen. After a delay, the navigation screen displays the last screen after the vehicle is shifted out of R (Reverse).

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Turning the RVC System On or Off To turn the RVC system on or off: 1. Shift into P (Park). 2. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

3. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

4. Select the Video screen button. When the Video screen button is highlighted the RVC system is on.

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Driving and Operating

The delay after shifting out of R (Reverse) is approximately 10 seconds. The delay can be canceled by performing one of the following: . Pressing a hard key on the

navigation system.

. Shifting into P (Park). . Reaching a vehicle speed of

8 km/h (5 mph).

Adjusting the Brightness and Contrast of the Screen To adjust the brightness and contrast of the screen, press the MENU button while the RVC image is on the display. Any adjustments made will only affect the RVC screen. ] (Brightness): Touch the + (plus) or – (minus) screen buttons to increase or decrease the brightness of the screen.

_ (Contrast): Touch the + (plus) or – (minus) screen buttons to increase or decrease the contrast of the screen.

Symbols The navigation system may have a feature that allows for viewing parking assist symbols on the navigation screen while using the RVC. The Ultrasonic Rear Park Assist (URPA) system must not be disabled to use the caution symbols. If URPA has been disabled and the symbols have been turned on, the Rear Parking Assist Symbols Unavailable error message may display. See Ultrasonic Parking Assist on page 9‑61. The symbols appear near objects detected by the URPA system. The symbol may cover the object when viewing the navigation screen. To turn the symbols on or off: 1. Make sure that URPA has not

been disabled.

2. Shift into P (Park).

3. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

4. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

5. Touch the Symbols screen

button. The screen button will be highlighted when on.

Guidelines The RVC system has a guideline overlay that can help the driver align the vehicle when backing into a parking spot. If the vehicle has dual rear wheels, this feature will not be available. To turn the guidelines on or off: 1. Make sure that URPA has not

been disabled.

2. Shift into P (Park).

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3. Press MENU to enter the

configure menu options. Turn the Multifunction knob until the Display feature is highlighted and press the Multifunction knob. Or press the Display screen button

4. Select the Rear Camera Options screen button. The Rear Camera Options screen displays.

5. Touch the Guidelines screen

button. The screen button will be highlighted when on.

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RVC Location

A. View displayed by the camera

The camera is located in the bezel for the tailgate handle. This shows the field of view that the camera provides.

A. View displayed by the camera B. Corners of the rear bumper

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Driving and Operating

Displayed images may be further or closer than they appear. The area displayed is limited and objects which are close to either corner of the bumper or under the bumper do not display.

Disconnecting the RVC The rear vision camera must be disconnected if the tailgate needs to be removed. To disconnect the camera: 1. Remove the license plate. 2. Disconnect the camera

connectors from the chassis harness, located behind the license plate, by pressing on the release tab on each connector.

A. Chassis harness connector B. Release tab C. Camera connector

3. Plug the two exposed chassis

harness connectors together to prevent contamination.

A. Chassis harness connector B. Release tab

4. Feed the wiring harness through

the pickup box, then plug the camera connectors together to prevent contamination.

5. Remove the tailgate. See

Tailgate on page 2‑10 for more information.

6. Reinstall the license plate.

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Reverse this procedure to reinstall the RVC and make sure the grommet and connection are secure. When the System Does Not Seem To Work Properly The RVC system might not work properly or display a clear image if:

The RVC is turned off. See “Turning the RVC System On or Off” earlier in this section. It is dark. The sun or the beam of headlamps is shining directly into the camera lens. Ice, snow, mud, or anything else builds up on the camera lens. Clean the lens, rinse it with water, and wipe it with a soft cloth.

The back of the vehicle is in an accident, the position and mounting angle of the camera can change or the camera can be affected. Be sure to have the camera and its position and mounting angle checked at your dealer.

The RVC system display in the rearview mirror may turn off or not appear as expected due to one of the following conditions. If this occurs the left indicator light on the mirror will flash. . A slow flash may indicate a loss

of video signal, or no video signal present during the reverse cycle.

. A fast flash may indicate that

the display has been on for the maximum allowable time during a reverse cycle, or the display has reached an Over Temperature limit.

The fast flash conditions are used to protect the video device from high temperature conditions. Once conditions return to normal the device will reset and the green indicator will stop flashing.

During any of these fault conditions, the display will be blank and the indicator will flash while the vehicle is in R (Reverse) or until the conditions return to normal. Press and hold z when the left indicator light is flashing to turn off the video display along with the left indicator light.

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Driving and Operating

Fuel For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax Diesel Supplement. For Vehicles with gasoline engines, please read this.

Gasoline Use of the recommended fuel is an important part of the proper maintenance of this vehicle. To help keep the engine clean and maintain optimum vehicle performance, we recommend the use of gasoline advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure gasoline meets enhanced detergency standards developed by auto companies. A list of marketers providing TOP TIER Detergent Gasoline can be found at www.toptiergas.com.

The eighth digit of the Vehicle Identification Number (VIN) shows the code letter or number that identifies the vehicle's engine. The VIN is at the top left of the instrument panel. See Vehicle Identification Number (VIN) on page 12‑1. Vehicles that have a FlexFuel badge and a yellow fuel cap can use either unleaded gasoline or ethanol fuel containing up to 85% ethanol (E85).

See Fuel E85 (85% Ethanol) on page 9‑71. For all other vehicles, use only the unleaded gasoline described under Recommended Fuel on page 9‑68.

Recommended Fuel For all vehicles except those with the 6.2L V8 engine (VIN Code 2), use regular unleaded gasoline with a posted octane rating of 87 or higher. If the octane rating is less than 87, an audible knocking noise, commonly referred to as spark knock, might be heard when driving. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service.

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If the vehicle has the 6.2L V8 engine (VIN Code 2), use premium unleaded gasoline with a posted octane rating of 91 or higher. You can also use regular unleaded gasoline rated at 87 octane or higher, but the vehicle's acceleration could be slightly reduced, and a slight audible knocking noise, commonly referred to as spark knock, might be heard. If the octane is less than 87, you might notice a heavy knocking noise when you drive. If this occurs, use a gasoline rated at 87 octane or higher as soon as possible. Otherwise, you could damage the engine. If heavy knocking is heard when using gasoline rated at 87 octane or higher, the engine needs service.

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Gasoline Specifications (U.S. and Canada Only) At a minimum, gasoline should meet ASTM specification D 4814
in the United States or CAN/CGSB‐3.5 or 3.511 in Canada. Some gasolines contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT). We recommend against the use of gasolines containing MMT. See Fuel Additives on page 9‑70 for additional information.

California Fuel Requirements If the vehicle is certified to meet California Emissions Standards, it is designed to operate on fuels that meet California specifications. See the underhood emission control label. If this fuel is not available in states adopting California Emissions Standards, the vehicle will operate satisfactorily on fuels meeting federal specifications, but emission

control system performance might be affected. The malfunction indicator lamp could turn on and the vehicle might fail a smog‐check test. See Malfunction Indicator Lamp on page 5‑22. If this occurs, return to your authorized dealer for diagnosis. If it is determined that the condition is caused by the type of fuel used, repairs might not be covered by the vehicle warranty.

Fuels in Foreign Countries Never use leaded gasoline or any other fuel not recommended in the previous text on fuel. Costly repairs caused by use of improper fuel would not be covered by the vehicle warranty. To check the fuel availability, ask an auto club, or contact a major oil company that does business in the country where you will be driving.

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Driving and Operating

Fuel Additives To provide cleaner air, all gasolines in the United States are now required to contain additives that help prevent engine and fuel system deposits from forming, allowing the emission control system to work properly. In most cases, nothing should have to be added to the fuel. However, some gasolines contain only the minimum amount of additive required to meet U.S. Environmental Protection Agency regulations. To help keep fuel injectors and intake valves clean and avoid problems due to dirty injectors or valves, look for gasoline that is advertised as TOP TIER Detergent Gasoline. Look for the TOP TIER label on the fuel pump to ensure gasoline meets enhanced detergency standards developed by the auto companies. A list of marketers providing TOP TIER Detergent Gasoline can be found at www.toptiergas.com.

For customers who do not use TOP TIER Detergent Gasoline regularly, one bottle of GM Fuel System Treatment PLUS, added to the fuel tank at every engine oil change, can help clean deposits from fuel injectors and intake valves. GM Fuel System Treatment PLUS is the only gasoline additive recommended by General Motors. It is available at your dealer. Gasolines containing oxygenates, such as ethers and ethanol, and reformulated gasolines might be available in your area. We recommend that you use these gasolines, if they comply with the specifications described earlier. However, E85 (85% ethanol) and other fuels containing more than 15% ethanol must not be used in vehicles that were not designed for those fuels.

Notice: This vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic and rubber parts. That damage would not be covered under the vehicle warranty. Some gasolines that are not reformulated for low emissions can contain an octane-enhancing additive called methylcyclopentadienyl manganese tricarbonyl (MMT); ask the attendant where you buy gasoline whether the fuel contains MMT. We recommend against the use of such gasolines. Fuels containing MMT can reduce spark plug life and affect emission control system performance. The malfunction indicator lamp might turn on. If this occurs, return to your dealer for service.

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At a minimum, E85 should meet ASTM Specification D 5798 or CGSB Specification 3.512. Filling the tank with fuel mixtures that do not meet ASTM or CGSB specifications can affect driveability and could cause the malfunction indicator lamp to come on. As the outside temperature approaches freezing, ethanol fuel distributors should supply winter grade ethanol, the same as with unleaded gasoline. It is best not to alternate repeatedly between gasoline and E85. If you do switch fuels, it is recommended that you add as much fuel as possible — do not add less than 11 L (3 gal) when refueling. You should drive the vehicle immediately after refueling for at least 11 km (7 mi) to allow the vehicle to adapt to the change in ethanol concentration.

E85 has less energy per liter (gallon) than gasoline, so you will need to refill the fuel tank more often when using E85 than when you are using gasoline. See Filling the Tank on page 9‑72. Notice: Some additives are not compatible with E85 fuel and can harm the vehicle's fuel system. Do not add anything to E85. Damage caused by additives would not be covered by the vehicle warranty. Notice: This vehicle was not designed for fuel that contains methanol. Do not use fuel containing methanol. It can corrode metal parts in the fuel system and also damage plastic