No Response From FDCM (Final Drive Control Module)

NO RESPONSE FROM FDCM (FINAL DRIVE CONTROL MODULE)












1. TEST FOR INTERMITTENT CONDITION
1. Turn the ignition on.

NOTE: Ensure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

2. With the scan tool, select ECU view.

NOTE: A red "X" will be next to the module that is not communicating, indicating that the module is not active on the Bus network. A green check indicates that the module is active on the Bus network.

NOTE: Check the FCM for any active CAN C hardware DTCs, perform DTC before proceeding.

Does the scan tool display a red "X" next to the module?

Yes

- Go To 2

No

- The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.

2. FUSED B(+) CIRCUIT OPEN OR SHORTED




1. Turn the ignition off.
2. Disconnect the Final Drive Control Module harness connectors.
3. Using a 12-volt test light connected to ground, check each Fused B(+) circuit.

Does the test light illuminate brightly for each circuit?

Yes

- Go To 3

No

- Repair the Fused B(+) circuit for an open or short.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test

3. GROUND CIRCUIT OPEN




1. Using a 12-volt test light connected to 12-volts, check each Ground circuit.

Does the test light illuminate brightly for each circuit?

Yes

- Go To 4

No

- Repair the ground circuit for an open.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test

4. (F921) FUSED RUN RELAY OUTPUT CIRCUIT OPEN OR SHORTED




1. Turn the ignition on.
2. Using a 12-volt test light connected to ground, check the (F921) Fused Run Relay Output circuit.

Does the test light illuminate brightly?

Yes

- Go To 5

No

- Repair the (F921) Fused Run Relay Output circuit for an open or short.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test

5. (D65) CAN C BUS (+) CIRCUIT OPEN




1. Turn the ignition off.
2. Disconnect the FCM C1 harness connector.
3. Measure the resistance of the (D65) CAN C Bus (+) circuit between the FCM connector and the FDCM connector.

Is resistance below 5.0 ohms?

Yes

- Go To 6

No

- Repair the (D65) CAN C Bus (+) circuit for an open.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test

6. (D64) CAN C BUS (-) CIRCUIT OPEN




1. Measure the resistance of the (D64) CAN C Bus (-) circuit between the FCM connector and the FDCM connector.

Is resistance below 5.0 ohms?

Yes

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

No

- Repair the (D64) CAN C Bus (-) circuit for an open.
- Perform the FDCM VERIFICATION TEST. FDCM Verification Test