Air Suspension
DTC C0625 or C0630
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 C0625 08
- Left Rear Position Sensor Circuit Signal Invalid
DTC C0625 55
- Left Rear Position Sensor Circuit Expected Number of Transitions/Events not Reached
DTC C0630 08
- Right Rear Position Sensor Circuit Signal Invalid
DTC C0630 55
- Right Rear Position Sensor Circuit Expected Number of Transitions/Events not Reached
Diagnostic Fault Information
Circuit/System Description
The left and right rear air suspension position sensors provide a signal voltage between 0.5-4.75 volts to the air suspension control module. This signal voltage represents the wheel's position relative to the body. The air suspension control module provides a 5-volt reference and a low reference to the sensors.
Conditions for Running the DTC
* Ignition voltage is between 9-16 volts.
* Vehicle is in motion.
Conditions for Setting the DTC
* The air suspension module detects the voltage at the strut position sensor signal circuit is less than 0.5 volt or greater than 4.75 volts for more than 500 milliseconds.
* The air suspension module detects that there is a wide differential between the signal voltage ranges of one sensor in comparison to the other over a predetermined period of time.
Action Taken When the DTC Sets
* Air suspension functionality is suspended.
* The SERVICE SUSPENSION SYSTEM message is displayed.
Conditions for Clearing the DTC
The condition for setting the DTC no longer exists.
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, observe the scan tool RR Position Sensor and LR Position Sensor parameters. The parameters should be between 0.5-4.75 volts.
Circuit/System Testing
1. Ignition OFF, remove the ELC MDL Fuse in the rear fuse block and disconnect the harness connector at the appropriate position sensor.
2. Test for less than 2.0 ohms between low reference circuit terminal 3 (LR) or terminal 1 (RR) and ground.
• If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the air suspension control module.
3. Install the ELC MDL Fuse in the rear fuse block.
4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 1 (LR) or terminal 3 (RR) and ground.
• If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
• If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the air suspension control module.
5. Verify the appropriate scan tool Position Sensor parameter is less than 0.5 volts.
• If greater than the specified range, test the signal circuit terminal 2 for a short to voltage. If the circuit tests normal, replace the air suspension control module.
6. Install a 3A fused jumper wire between the signal circuit terminal 2 and the 5-volt reference circuit terminal 1 (LR) or terminal 3 (RR). Verify the appropriate scan tool Position Sensor parameter is greater than 4.8 volts.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the air suspension control module.
7. If all circuits test normal, test or replace the rear suspension position sensor.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Air Spring Leveling Sensor Replacement (Removal and Replacement)
* Suspension Position Calibration (Suspension Position Calibration)
* Control Module References (Programming and Relearning) for air suspension control module replacement, setup, and programming