Manufacturer communication — 2006 GMC YUKON DENALI XL

• Applies to 2001-2013 GMC Yukon, Yukon XL LD, Yukon Denali and Yukon Denali XL (note: the years run later than the years this service covers).

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  2001-2013 GMC Yukon, Yukon XL LD, Yukon Denali, Yukon Denali XL

• Vehicles with RPO Z55 or Z95 are covered.

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  With RPO Z55 or Z95

• Condition 1 (2009 or prior vehicles): a Service Suspension System message on the DIC with incorrect rear ride height, and DTC C0696 or C0711 set in the Electronic Suspension Control (ESC) module.

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  Some customers of 2009 or prior vehicles, may comment of a Service Suspension System message on the DIC and the rear suspension ride height is incorrect. When checking for DTCs the Electronic Suspension Control (ESC) module will have DTC C0696 or C0711 set.

• Condition 2: a Service Suspension System message on the DIC, possibly with low rear ride height under a heavy payload, and DTC C0711 set in the ESC module.

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  Some customers may comment of a Service Suspension System message on the DIC and may also comment that the rear suspension ride height may be low under a heavy payload. When checking for DTCs the Electronic Suspension Control (ESC) module will have DTC C0711 set.

• Condition 3: a loose hose hangs down at the left rear; upon inspection the hose may be found damaged or disconnected from the air inlet filter of the auto leveling suspension air compressor.

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  Some customers may comment of a loose hose hanging down in the left rear of the vehicle. Upon inspection it may be determined that the hose is damaged or has become disconnected from the air inlet filter of the auto leveling suspension air compressor.

Possible causes

• Condition 1 can be caused by the wiring to the automatic level control (ALC) pressure sensor being shorted to ground.

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  This concern could be caused by the wiring to the automatic level control (ALC) pressure sensor being shorted to ground, as shown below.

• Condition 2 may be caused by an internal fault in the ALC pressure sensor, which can occur when moisture gets into the sensor.

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  This concern may be caused by an internal fault in the automatic level control (ALC) pressure sensor. This may occur due to moisture getting into the sensor.

Steps to confirm (in the document’s order)

1. The air compressor assembly may have to be removed to see whether the wiring is pinched between the compressor assembly and the frame.

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   The air compressor assembly may need to be removed from the vehicle to determine if the wiring is possibly pinched between the compressor assembly and frame.

2. If system pressure at start up is below 10 psi (69 kpa), the system runs the compressor to add air to the shocks as a replenishment cycle.

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   If the pressure is below 10 psi (69 kpa) then the system will operate the compressor to add air to the shocks as a replenishment cycle.

Repair

1. For condition 1, repair any damaged or shorted circuits and reposition the wiring so it is not damaged again when the compressor assembly is installed.

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   Repair any damaged or shorted circuits and then reposition the wiring so it does not get damaged again during the compressor assembly installation.

2. The sensor is no longer serviced separately; to replace it, install a complete air filter, dryer and sensor assembly.

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   The sensor is no longer serviced separately. For sensor replacement, install a complete air filter, dryer, and sensor assembly.

3. For condition 3, replace the auto leveling compressor air inlet filter and hose assembly (PN 22197160).

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   Replace the auto leveling compressor air inlet filter and hose assembly (PN 22197160), shown below.

Parts

• Vehicles built before May, 2012 need a jumper harness for the updated sensor, which is included with assembly PN 22964558; vehicles built in May, 2012 and later need no jumper harness and use PN 22941807.

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  Vehicles built before May, 2012, will require a jumper harness for the updated sensor design. The jumper harness is included with complete air filter, dryer, and sensor assembly, PN 22964558. Vehicles built in May, 2012 and later do not require the jumper harness, and use PN 22941807.

Caution

• Do not replace the complete air compressor assembly for this concern.

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  DO NOT replace the complete air compressor assembly for this concern.

• Condition 4 (no compressor self test at start up): the automatic level system normally does not, or only very infrequently does, cycle the compressor at key up.

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  The automatic level system normally will not or very infrequently cycle the compressor at key up.