DTC B1C84:14 [FRONT BODY CONTROL MODULE (FBCM)]


id0902p2009400

Description

Rear window defroster relay circuit malfunction

Detection condition
•  Front body control module (FBCM) detects an open circuit or short to ground in the rear window defroster relay circuit with the ignition switched ON (engine off or on).
Fail-safe function
Not applicable
Possible cause
•  Rear window defroster relay malfunction
•  Front body control module (FBCM) connector or terminal malfunction
•  Short to ground in wiring harness between rear window defroster relay terminal E and front body control module (FBCM) terminal 1P
•  Open circuit in wiring harness between rear window defroster relay terminal E and front body control module (FBCM) terminal 1P
•  Front body control module (FBCM) malfunction

Diagnostic Procedure

Step

Inspection

Action

1
VERIFY FRONT BODY CONTROL MODULE (FBCM) DTCs AGAIN
•  Clear the DTC for the front body control module (FBCM) using the M-MDS.
•  Retrieve the front body control module (FBCM) DTCs using the M-MDS.
•  Is the same DTC displayed?
Yes
Go to the next step.
No
Go to Step 7.
2
INSPECT REAR WINDOW DEFROSTER RELAY
•  Switch the ignition off.
•  Remove the rear window defroster relay.
•  Inspect the rear window defroster relay.
•  Is the rear window defroster relay normal?
Yes
Go to the next step.
No
Replace the rear window defroster relay, then go to Step 6.
3
INSPECT FRONT BODY CONTROL MODULE (FBCM) CONNECTOR CONDITION
•  Disconnect the front body control module (FBCM) connector.
•  Inspect the connector engagement and connection condition and inspect the terminals for damage, deformation, corrosion, or disconnection.
•  Is the connector normal?
Yes
Go to the next step.
No
Repair or replace the connector, then go to Step 6.
4
INSPECT FOR SHORT TO GROUND IN REAR WINDOW DEFROSTER RELAY CONTROL CIRCUIT
•  Verify that the rear window defroster relay is removed.
•  Verify that the front body control module (FBCM) connector is disconnected.
•  Inspect for continuity between front body control module (FBCM) terminal 1P (wiring harness-side) and body ground.
•  Is there continuity?
Yes
Refer to the wiring diagram and verify whether or not there is a common connector between rear window defroster relay terminal E and front body control module (FBCM) terminal 1P.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for a short to ground.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has a short to ground.
Go to Step 6.
No
Go to the next step.
5
INSPECT FOR OPEN CIRCUIT IN REAR WINDOW DEFROSTER RELAY CONTROL CIRCUIT
•  Verify that the rear window defroster relay is removed.
•  Verify that the front body control module (FBCM) connector is disconnected.
•  Inspect for continuity between rear window defroster relay terminal E (wiring harness-side) and front body control module (FBCM) terminal 1P (wiring harness-side).
•  Is there continuity?
Yes
Go to the next step.
No
Refer to the wiring diagram and verify whether or not there is a common connector between rear window defroster relay terminal E and front body control module (FBCM) terminal 1P.
If there is a common connector:
•  Determine the malfunctioning part by inspecting the common connector and the terminal for corrosion, damage, or pin disconnection, and the common wiring harness for an open circuit.
•  Repair or replace the malfunctioning part.
If there is no common connector:
•  Repair or replace the wiring harness which has an open circuit.
Go to the next step.
6
VERIFY THAT REPAIRS HAVE BEEN COMPLETED
•  Always reconnect all disconnected connectors.
•  Clear the DTC for the front body control module (FBCM) using the M-MDS.
•  Retrieve the front body control module (FBCM) DTCs using the M-MDS.
•  Is the same DTC displayed?
Yes
Repeat the inspection from Step 1.
•  If the malfunction recurs, replace the front body control module (FBCM).
Go to the next step.
No
Go to the next step.
7
VERIFY IF OTHER DTCs DISPLAYED
•  Are any other DTCs displayed?
Yes
Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.
No
DTC troubleshooting completed.