Air Suspension

DTC C0660

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Diagnostic Procedure Instructions) provides an overview of each diagnostic category.

DTC Descriptors
DTC C0660 00
- Level Control Exhaust Circuit

DTC C0660 58
- Level Control Exhaust Circuit Incorrect Reaction After Event

Diagnostic Fault Information





Circuit Description

The air suspension control module (ASCM) controls the compressor relay and exhaust valve ground to maintain the height of the vehicle based on voltage signals from the rear height sensors. The ASCM raises and lowers the vehicle in order to keep the vehicle level.

Conditions for Running the DTC

Battery voltage is between 9-16 volts.

Conditions for Setting the DTC

* The exhaust valve control circuit is shorted to voltage, ground, or open when solenoid activation is commanded ON for 2.5 seconds.
* The exhaust valve B+ circuit is shorted to ground or open when solenoid activation is commanded ON for 5 seconds.
* Any component voltage supply circuit from the air suspension control module that is shorted to ground.
* Any suspension position sensor low reference circuit that is shorted to voltage.

Action Taken When the DTC Sets

* The air suspension system will be inoperative.
* The DIC will display SERVICE SUSPENSION SYS.

Conditions for Clearing the MIL/DTC

* DTC C0660 will change from a current DTC to a history DTC on the next ignition cycle.
* DTC C0660 will be cleared from history after 50 ignition cycles.

Reference Information
Schematic Reference

Air Suspension Schematics (Air Suspension Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Air Suspension Description and Operation (Air Suspension Description and Operation)
Electrical Information Reference

* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing For Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information

Circuit/System Verification

Ignition ON, command the air suspension exhaust solenoid valve ON and OFF with the scan tool. The exhaust solenoid valve should turn ON and OFF with each command.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the air suspension compressor exhaust solenoid.
2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal and ground.

• If the test lamp does not illuminate, test for the following conditions listed below. If all circuits test normal, replace the air suspension compressor assembly.

* An open, short to ground, or short to voltage in the air suspension exhaust valve solenoid control circuit
* A short to ground in one of the B+ or 5-volt reference circuits from the air suspension control module
* A short to voltage in one of the position sensor low reference circuits

3. Connect a test lamp between the B+ circuit terminal and the control circuit terminal.
4. Command the exhaust solenoid ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the air suspension control module.
• If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the air suspension control module.

5. If all circuits test normal, replace the air suspension compressor assembly.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Automatic Level Control Air Compressor Replacement (Automatic Level Control Air Compressor Replacement)
* Suspension Position Calibration (Suspension Position Calibration)
* Control Module References (Programming and Relearning) for air suspension control module replacement, setup and programming