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. |
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Air Suspension Compressor Assembly Battery Positive Voltage Circuit | 1, 2, 4, 6 | 1, 2, 4, 6 | -- | -- |
Air Suspension Compressor Assembly Ignition 3 Voltage Circuit | 1, 2, 4, 6 | 1, 2, 4, 6 | -- | -- |
Air Suspension Compressor Assembly Ground Circuit | -- | 1, 2, 4, 6 | -- | -- |
Air Suspension Inflator Switch Ground Circuit | -- | 4, 6 | -- | -- |
Air Suspension Inflator Switch Indicator Control Circuit | 4 | 4 | 3 | -- |
Air Suspension Inflator Switch Signal Circuit | 5 | 6 | 6 | -- |
Left Rear Air Suspension Sensor Low Reference Circuit | -- | DTC 002 | -- | -- |
Left Rear Air Suspension Sensor Signal Circuit | DTC 002 | DTC 002 | DTC 002 | -- |
Right Rear Air Suspension Sensor Low Reference Circuit | -- | DTC 003 | -- | -- |
Right Rear Air Suspension Sensor Signal Circuit | DTC 003 | DTC 003 | DTC 003 | -- |
Vehicle Speed Signal Circuit | B0540 | 7 | B0540 | -- |
1. Air Springs Do Not Deflate 2. Air Springs Do Not Inflate 3. Air Suspension Inflator Switch Indicator Always ON 4. Air Suspension Inflator Switch Indicator Inoperative 5. Inflator Always ON 6. Inflator Inoperative 7. Inflator Will Operate While Vehicle is in Motion | ||||
Circuit/System Description
The air suspension system utilizes left and right rear air suspension sensors to determine the calibrated level of the vehicle. As weight is added to the rear of the vehicle, the sensors signal to the air suspension compressor change which activates the compressor to raise the vehicle to the proper height. Upon removal of the additional weight, the sensor signals the compressor to exhaust enough air to lower the vehicle back down to maintain the calibrated rear trim height.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Air Suspension Description and Operation
Electrical Information Reference
Circuit/System Verification
Ignition ON, load the vehicle with additional weight in the rear. The air suspension compressor should activate raising the vehicle to the calibrated vehicle level. Remove the additional load and the compressor will exhaust the necessary amount of air to return to the calibrated vehicle level.
Circuit/System Testing
- Inspect the air delivery system for damaged air springs or supply lines.
- Ignition OFF, disconnect the harness connector at the air suspension compressor assembly.
- Test for less than 2.0 ohms between the low reference circuit connector X1, terminal D and ground.
- Ignition ON, verify that a test lamp illuminates between the compressor B+ circuit connector X1, terminal H and ground.
- Ignition ON, verify that a test lamp illuminates between the compressor IGN 3 circuit connector X1, terminal G and ground.
| ⇒ | If any damage is found, perform the Air Suspension Air Leak Diagnosis and repair or replace any leaking component as necessary. |
| ⇒ | If greater than the specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the air suspension compressor assembly. |
| ⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the air suspension compressor assembly. |
| ⇒ | If the test lamp does not illuminate, test the IGN 3 circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the air suspension compressor assembly. |
| ⇒ | If the circuit tests normal, replace the air suspension compressor assembly. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
