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

Step

Inspection

Action

1

• Clear the DTC for the front body control module (FBCM) using the M-MDS.

  (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)].)

• 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.

No

Go to Step 7.

2

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

• 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.

No

Replace the rear window defroster relay, then go to Step 6.

(See RELAY LOCATION.)

3

• 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

• 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

• 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

• Always reconnect all disconnected connectors.

• Reconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

• Clear the DTC for the front body control module (FBCM) using the M-MDS.

  (See CLEARING DTC [FRONT BODY CONTROL MODULE (FBCM)].)

• 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.

No

Go to the next step.

7

• 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)].)

No

DTC troubleshooting completed.