No Response From FCM (Front Control Module)
NO RESPONSE FROM FCM (FRONT CONTROL MODULE)No Response From FCM (Front Control Module):
POSSIBLE CAUSES
- (A918) Fused B(+) circuit open at DLC
- (Z11) Ground circuit open at DLC
- Ground circuits open at FCM
- Fused B+ circuits open at FCM
- Front control module
Diagnostic Test
1. TEST FOR INTERMITTENT CONDITION
Turn the ignition on.
NOTE:
- Ensure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.
- Ensure the scan tool is updated to the latest software.
- If the scan tool displays any error messages involving the CAN C Diagnostic circuits, diagnose and repair the error message before proceeding.
- A loss of communication with the FCM can cause the ECU View button on the scan tool to be inoperative (not highlighted).
With the scan tool, attempt to select ECU view.
Q: Can the scan tool communicate with the FCM?
YES: 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.
NO: Go To 2
2. (A918) FUSED B(+) CIRCUIT OPEN AT DLC
Disconnect the scan tool from the DLC.
NOTE: Check IPM fuses before continuing.
Using a 12-volt test light connected to ground, check the (A918) Fused B(+) circuit.
Q: Does the test light illuminate brightly?
YES: Go To 3
NO: Repair the (A918) Fused B(+) circuit for an open or short.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
3. (Z11) GROUND CIRCUIT OPEN AT DLC
Using a 12-volt test light connected to 12-volts, check the (Z11) ground circuit.
Q: Does the test light illuminate brightly?
YES: Go To 4
NO: Repair the (Z11) ground circuit for an open.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
4. GROUND CIRCUITS OPEN AT FCM C1 AND C2 CONNECTORS
Disconnect the FCM C1 and C2 harness connectors.
Using a 12-volt test light connected to 12-volts, check each ground circuit.
Q: Does the test light illuminate brightly for each circuit?
YES: Go To 5
NO: Repair the ground circuit for an open. Inspect the connector for damage.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
5. GROUND CIRCUITS OPEN AT FCM IPM CONNECTOR
Remove the FCM from the IPM.
Using a 12-volt test light connected to 12-volts, check each ground circuit.
Q: Does the test light illuminate brightly for each circuit?
YES: Go To 6
NO: Repair the ground circuit for an open. Inspect the connector for damage.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
6. FUSED B(+) CIRCUITS OPEN AT FCM IPM CONNECTOR
NOTE: Check IPM fuses before continuing.
Using a 12-volt test light connected to ground, check each Fused B(+) circuit.
Q: Does the test light illuminate brightly for each circuit?
YES: Replace and program the Front Control Module.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Repair the Fused B(+) circuit for an open. Inspect the connector for damage. If ok, replace the PDC portion of the IPM.
Perform BODY VERIFICATION TEST - VER 1. Body Verification Test