Some 2001-2013 Cadillac Escalades may show a Service Suspension System message on the DIC, and the rear suspension height may be incorrect. When checking for DTCs, the ESC (electronic suspension control) module will have C0696 or C0711 set.
This concern could be caused by the wiring to the automatic level control (ALC) pressure sensor being shorted to ground. The air compressor may need to be removed to determine if the wiring is possibly pinched between the compressor and frame. According to GM, do not replace the complete air compressor assembly for this concern. Repair any damaged or shorted circuits, and then reposition the wiring to prevent future damage.
The rear suspension may be low under a heavy payload. When checking, the ESC module may have set DTC C0711. This could be caused by an internal fault in the automatic level control pressure sensor, due to moisture in the sensor. An improved sensor design is available that will require a jumper harness. The jumper harness is included with a complete air filter, dryer and sensor assembly, P/N 22964558.
Vehicles built in May 2012 and later do not require the jumper harness, and use P/N 22941807. Make sure that the sensor wiring is routed carefully under and around the air filter, dryer and sensor assembly during compressor installation.
Some customers may comment that the automatic level control compressor is no longer performing a self test at startup (where the compressor should activate for a few seconds at startup). Replace the auto leveling compressor air inlet filter and hose assembly P/N 22197160. Raise the vehicle on a hoist and release the air compressor air inlet filter from the retainer securing the rear axle vent hose and compressor air inlet to the fuel fill pipe. Remove the remaining air inlet hose from the air compressor. Install the new air inlet filter and hose assembly.
The automatic level system normally will not cycle the compressor at key-up. The ESC module checks the automatic level system pressure at start=up. If the pressure is below 10 psi, the system will operate the compressor to add air to the shocks as a replenishment cycle. This typically only happens if the vehicle sat for a long period of time or if there is a very small leak.