Diagnostic Instructions
| • | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
| • | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
| • | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
DTC Descriptors
DTC C0660 01: Level Control Exhaust Circuit Short to BatteryDTC C0660 06: Level Control Exhaust Circuit Short to Ground or Open Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Automatic Level Control Exhaust Solenoid Control Circuit | C0660 06 | C0660 06 | C0660 01 | -- |
Automatic Level Control Exhaust Solenoid Supply Voltage Circuit | C0660 06 | C0660 06 | -- | -- |
Circuit Description
The electronic suspension control module (ESCM) adjusts the vehicle suspension ride height. The ESCM determines the height of the vehicle based on signals from the height sensors. The ESCM raises and lowers the vehicle in order to keep the vehicle level by controlling the exhaust valve and air compressor control circuits.
Conditions for Running the DTC
| • | Battery voltage is between 9-16 volts. |
| • | The exhaust valve is commanded ON. |
Conditions for Setting the DTC
| • | The exhaust solenoid control circuit is shorted to voltage, ground, or open when solenoid activation is commanded ON for 2.5 seconds. |
| • | The exhaust solenoid supply voltage circuit is shorted to ground or open when solenoid activation is commanded ON for 5 seconds. |
Action Taken When the DTC Sets
| • | The electronic suspension control system will be inoperative. |
| • | The SERVICE SUSPENSION SYSTEM message will be displayed. |
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
Automatic Level Control Schematics
Connector End View Reference
Description and Operation
Automatic Level Control Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Ignition ON, command the Exhaust Valve ON and OFF with the scan tool output control. The exhaust solenoid valve should turn ON and OFF with each command.
Circuit/System Testing
- Ignition OFF, disconnect the automatic level control (ALC) compressor exhaust solenoid.
- Ignition ON, verify that a test lamp does not illuminate between the solenoid control circuit terminal C at the connector and ground.
- Verify that a test lamp illuminates between the B+ circuit terminal B and ground.
- Connect a test lamp between the B+ circuit terminal B and the control circuit terminal C.
- With a scan tool, clear all ALC DTCs.
- Command the exhaust solenoid ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.
- If all circuits test normal, test or replace the ALC compressor.
| ⇒ | If the test lamp illuminates, test the control circuit for a short to voltage. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuits for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the ALC compressor. |
| ⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the ESCM. |
| ⇒ | 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 ESCM. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for ESCM replacement, setup, and programming |
