C144B

C144B-REAR DIFFERENTIAL RETURN CIRCUIT HIGH





For a complete wiring diagram Refer to the Wiring Information.

- When Monitored:
Ignition on. Disconnecting Stabilizer Bar Switch in the RR or FR/RR position.

- Set Condition:
The FDCM detects the Rear Locker Source circuit is shorted low.





1. ACTIVE DTC

CAUTION: Before removing the FDCM harness connector, clean the connector and locking cam area of dirt and debris. Failure to do so can result in the connector being jammed or damage to the locking cams on the harness connector or module. Do not force the assist arm when releasing or installing the harness connector.

1. Ignition on, engine not running.
2. With the scan tool, read DTCs.

Is the DTC active at this time?

Yes

- Go To 2

No

- Go To 6

2. REAR LOCKER SOLENOID OPERATION

NOTE: Before continuing with the below diagnostic test, ensure the FDCM harness connector seal is installed correctly. Inspect the terminals on both harness connector and the module for damage. Failure to do so can result in misdiagnoses of the system.

1. Turn the ignition off.
2. Disconnect the Rear Locker Solenoid harness connector.
3. Ignition on, engine not running.
4. Using a 12-volt test light, jump across from the (T526) Rear Locker Source circuit and the (T528) Rear Locker Return circuit in the Rear Locker harness connector.
5. With a scan tool, actuate the Rear Locker Solenoid.

Does the test light flash on and off?

Yes

- Inspect the Rear Locker Solenoid terminals and connectors for corrosion and/or dirt that may compromise the connection. If OK, replace the Rear Locker Solenoid.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Go To 3

3. (T528) REAR LOCKER RETURN CIRCUIT SHORTED TO BATTERY VOLTAGE




1. Turn the ignition off.
2. Disconnect the FDCM harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (T528) Rear Locker Return circuit at the FDCM harness connector.

Does the voltmeter indicate voltage present?

Yes

- Repair the short to voltage in the (T528) Rear Locker Return circuit.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Go To 4

4. (T528) REAR LOCKER RETURN CIRCUIT SHORTED TO (T526) REAR LOCKER SOURCE CIRCUIT




1. Turn the ignition off.
2. Measure the resistance between the (T526) Rear Locker Source circuit and the (T528) Rear Locker Return circuit in the FDCM harness connector.

Is the resistance below 100 ohms?

Yes

- Repair the short between (T526) Rear Locker Source circuit and the (T528) Rear Locker Return circuit.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Go To 5

5. FDCM

NOTE: Before continuing, check the FDCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.

1. Using the schematics as a guide, inspect the wire harness and connectors. Pay particular attention to all Power and Ground circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Replace and program the Final Drive Control Module.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

6. INTERMITTENT WIRING AND CONNECTORS
1. The conditions necessary to set this DTC are not present at this time.
2. Using the schematics as a guide, inspect the wiring and connectors specific to this circuit.
3. Wiggle test the wiring harness and connectors while checking for shorted and open circuits.
4. Using the scan tool, monitor the data related to this circuit while performing the wiggle test. Look for the data to change or for the DTC to reset.

Were there any problems found?

Yes

- Repair as necessary.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Test Complete.