C15AD

C15AD-92-RIDE HEIGHT SYSTEM - PERFORMANCE OR INCORRECT OPERATION

For a complete wiring diagram, refer to the Wiring Information.





- When Monitored:
Ignition on. Battery voltage between 9 and 16 volts.

- Set Condition:
When the Air Suspension Control Module (ASCM) checks for ride height sensor movement during the middle of a level change. If it does not see this movement then this DTC is set.





Diagnostic Test

1. VERIFY THE DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, record and erase DTCs.
3. With the scan tool, read the DTCs in the ASCM.

Is the DTC active at this time?

Yes

- Go To 2

No

- Go To 8

2. AIR SUSPENSION RELAY FUSE F5 (40A)
1. Turn the ignition off.
2. Check the Air Suspension Relay Fuse F5 (40A) in the PDC.

Were any problems found?

Yes

- Repair as necessary.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

No

- Go To 3

3. AIR SUSPENSION COMPRESSOR RELAY
1. Install the Air Suspension Relay Fuse F5 (40A) in the PDC.
2. Remove the Air Suspension Relay and install a known good relay.
3. Turn the ignition on.
4. Use the Terrain Select Switch and select the next highest level.
5. With the scan tool, read the DTCs in the ASCM.

Does the DTC remain active?

Yes

- Go To 4

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

4. (A206) FUSED B(+) OPEN OR HIGH RESISTANCE




1. Turn the ignition off.
2. Remove the Air Suspension Relay.
3. Turn the ignition on.
4. Using a 12 volt test light connected to ground, check the (A206) Fused B+ circuit.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the (A206) Fused B+ circuit for an open or high resistance.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

5. (Z915) GROUND OPEN OR HIGH RESISTANCE




1. Turn the ignition off.
2. Using a 12-volt test light connected to 12-volts, check the (Z915) Ground circuit at the Air Suspension Relay.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes

- Go To 6

No

- Repair the (Z915) Ground circuit for an open or high resistance.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

6. (Y40) COMPRESSOR RELAY OUTPUT OPEN OR HIGH RESISTANCE




1. Install the Air Suspension Relay in the PDC.
2. Disconnect the Air Suspension Compressor Assembly harness connector.
3. Measure the resistance of the (Y40) Compressor Relay Output circuit between the ASCM C2 harness connector and the Air Suspension Compressor Assembly harness connector.

Is the resistance above 5.0 Ohms?

Yes

- Repair the (Y40) Compressor Relay Output circuit for an open or high resistance.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

No

- Go To 7

7. AIR SUSPENSION COMPRESSOR ASSEMBLY




1. Connect the Air Suspension Compressor Assembly harness connector.
2. While back probing, measure the resistance between the (Y40) Fused (B+) circuit and the (Z915) Ground circuit at the Air Suspension Compressor Assembly.

Is the resistance above 5 Ohms?

Yes

- Replace the Air Suspension Compressor Assembly. Air Suspension Compressor Assembly - Removal.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

No

- Replace the Air Suspension Control Module (ASCM). Air Suspension Control Module - Removal.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

8. INTERMITTENT WIRING AND CONNECTORS
1. Using the wiring diagram/schematic as a guide, inspect the wiring harness and connectors.
2. Wiggle test the wiring harness and connectors while monitoring the scan tool data relative to this circuit.
3. Look for the data to change or for the DTC to reset during the wiggle test.
4. While monitoring the scan tool data relative to this circuit, move the selector switch to each position several times.
5. Look for the data to change other than as expected or for the DTC to reset.

Were any problems found?

Yes

- Repair as necessary.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time.