C0655

DTC C0655

Circuit Description
The vehicle's rear leveling compressor motor is switched on and off via a compressor motor relay which is controlled by the suspension control module. The suspension control module provides a switched path to ground whenever compressor activity is required. The suspension control module continually monitors the compressor motor relay circuitry to determine if the voltage level agrees with the commanded state.

Conditions for Running the DTC
Whenever the compressor is activated.

Conditions for Setting the DTC
^ Open in the control circuit of the compressor motor relay
^ Short to ground in the control circuit of the compressor motor relay
^ Short to battery in the control circuit of the compressor motor relay
^ Open in the ignition 3 voltage circuit of the compressor motor relay
^ Open ION 3 fuse
^ A malfunctioning compressor motor relay

Action Taken When the DTC Sets
^ The compressor motor relay is disabled for the remainder of the ignition cycle.
^ Stores a DTC C0655 in the suspension control module memory

Conditions for Clearing the DTC
^ The suspension control module no longer detects a open, short to ground, or a short to battery in the control circuit of the compressor motor relay.
^ Using a scan tool
^ A history DTC will clear after 100 consecutive ignition cycles if the condition for the malfunction is no longer present.

Diagnostic Aids

Important: A leak in the air tube between the rear shocks and compressor will cause excessive running of the compressor motor. After approximately 5 minutes of continuous running without a change in body-to-wheel height or system pressure, the suspension control module will command the compressor motor relay to the off state for the remainder of the ignition cycle.

The following conditions may cause a malfunction to occur in the compressor motor relay:
^ A short to ground in the control circuit
^ An open in the control circuit
^ A short to battery in the control circuit
^ An open in the ignition 3 voltage circuit

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Command both the ON and OFF states. Repeat the commands as necessary.
3. Tests the coil of the relay for continuity.
4. Tests for voltage at the coil side of the compressor motor relay. The ION 3 fuse supplies power to the coil side of the compressor motor relay.
5. Verifies that the suspension control module is providing ground to the compressor motor relay.
6. Tests if ground is constantly being applied to the compressor motor relay.
7. Test for a short to voltage or an open in the control circuit of the compressor motor relay.
13. The replacement suspension control module must be calibrated.

Steps 1 - 2:

Steps 3 - 14:

DTC C0655