DTC B1C84:12 [FRONT BODY CONTROL MODULE (FBCM)]

id0902p2009300

Description

Rear window defroster relay circuit malfunction

Detection condition

•  Front body control module (FBCM) detects a short to power supply 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 power supply in wiring harness between rear window defroster relay terminal E and front body control module (FBCM) terminal 1P

•  Front body control module (FBCM) malfunction

Description	Rear window defroster relay circuit malfunction
Detection condition	• Front body control module (FBCM) detects a short to power supply 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 power supply 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. (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)].) • Operate the rear window defroster by pushing the rear window defroster switch. • Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See DTC INSPECTION [FRONT BODY CONTROL MODULE (FBCM)].) • Is the same DTC displayed?	Yes	Go to the next step.
1		No	Go to Step 6.
2	INSPECT REAR WINDOW DEFROSTER RELAY • Switch the ignition off. • Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) • Remove the rear window defroster relay. (See RELAY LOCATION.) • Inspect the rear window defroster relay. (See RELAY INSPECTION.) • Is the rear window defroster relay normal?	Yes	Go to the next step.
2		No	Replace the rear window defroster relay, then go to Step 5. (See RELAY LOCATION.)
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.
3		No	Repair or replace the connector, then go to Step 5.
4	INSPECT FOR SHORT TO POWER SUPPLY 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. • Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) • Switch the ignition ON (engine off or on). • Measure the voltage at the front body control module (FBCM) terminal 1P (wiring harness-side). • Is the voltage 0 V?	Yes	Go to the next step.
4		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 a short to power supply. • Repair or replace the malfunctioning part. If there is no common connector: • Repair or replace the wiring harness which has a short to power supply. Go to the next step.
5	VERIFY THAT REPAIRS HAVE BEEN COMPLETED • Always reconnect all disconnected connectors. • Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 1.5, SKYACTIV-G 2.0, SKYACTIV-G 2.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 1.5].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-D 2.2].) (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [MZR 1.6].) • Clear the DTC for the front body control module (FBCM) using the M-MDS. (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)].) • Operate the rear window defroster by pushing the rear window defroster switch. • Retrieve the front body control module (FBCM) DTCs using the M-MDS. (See DTC INSPECTION [FRONT BODY CONTROL MODULE (FBCM)].) • Is the same DTC displayed?	Yes	Repeat the inspection from Step 1. • If the malfunction recurs, replace the front body control module (FBCM). (See FRONT BODY CONTROL MODULE (FBCM) REMOVAL/INSTALLATION.) Go to the next step.
5		No	Go to the next step.
6	VERIFY IF OTHER DTCs DISPLAYED • Are any other DTCs displayed?	Yes	Repair or replace the malfunctioning part according to the applicable DTC troubleshooting. (See DTC TABLE [FRONT BODY CONTROL MODULE (FBCM)].)
6		No	DTC troubleshooting completed.