Final Drive Control Module (FDCM)

C2112-SENSOR SUPPLY 1 VOLTAGE CIRCUIT HIGH







- When Monitored:
Ignition on.

- Set Condition:
The FDCM recognizes the Locker Sensor Supply circuit voltage is too high.





1. ACTIVE DTC

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

Is the DTC active at this time?

Yes

- Go To 2

No

- Go To 5

2. FRONT DIFFERENTIAL POSITION SENSOR





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. Turn the ignition off.
2. Disconnect the Front Locker Solenoid harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (T521) Locker Sensor 1 Supply circuit in the Front Locker Solenoid harness connector.

Is the voltage above 4.5 volts?

Yes

- Replace the Front Locker Solenoid.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Go To 3

3. (T521) LOCKER SENSOR 1 SUPPLY CIRCUIT SHORTED TO VOLTAGE




1. Turn the ignition off.
2. Disconnect the FDCM harness connector.
3. Turn the ignition on.
4. Measure the voltage of the (T521) Locker Sensor 1 Supply circuit at the FDCM harness connector.

Does the voltmeter indicate voltage present?

Yes

- Repair the short to voltage in the (T521) Locker Sensor 1 Supply circuit.
- Perform FDCM VERIFICATION TEST.FDCM Verification Test

No

- Go To 4

4. 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

5. 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.