Air Suspension Control Module (ASCM)

C211B-92-IGNITION RUN/START INPUT CIRCUIT PERFORMANCE - PERFORMANCE OR INCORRECT OPERATION

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

NOTE:
Repair all other DTCs first before continuing with this diagnostic procedure.





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

- Set Condition:
The Air Suspension Control Module (ASCM) senses ignition run start from two inputs, one is from the CAN messaging and the other is from the hardwired input. When there is a conflict in ignition status this fault sets.





Diagnostic Test

1. DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, record and erase the DTCs.
3. With the scan tool, read the DTCs in the ASCM.

Is the DTC status Active at this time?

Yes

- Go To 3

No

- Go To 4

2. (F943) FUSED IGNITION SWITCH OUTPUT (RUN/START) CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition off to the lock position.
2. Disconnect the ASCM C2 harness connector.
3. Measure the voltage between ground and (F943) Fused Ignition Switch Output (Run/Start) harness connector.

Is the voltage above 9 volts?

Yes

- Repair the (F943) Fused Ignition Switch Output (Run/Start) circuit for a short to voltage.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

No

- Go To 3

3. (F943) FUSED IGNITION SWITCH OUTPUT (RUN/START) CIRCUIT OPEN OR HIGH RESISTANCE




1. Ignition on, engine not running.
2. With a 12-volt test light connected to ground, check the (F943) Fused Ignition Switch Output (Run/Start) circuit in the ASCM C2 harness connector.

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

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

No

- Repair the (F943) Fused Ignition Switch Output (Run/Start) circuit for an open circuit or high resistance.
- Perform the ASCM VERIFICATION TEST. ASCM Verification Test.

4. 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.