Description

Front body control module (FBCM) power supply voltage mismatch

Detection condition

• Front body control module (FBCM) terminal 1A, 1B, 3K, and 3L voltages of 2 V or more lower than the voltage of terminal 2A are detected for 5 s or more with the ignition switched ON (engine off or on).

Fail-safe function

Not applicable

Possible cause

• Front body control module (FBCM) connector or terminal malfunction

• Front body control module (FBCM) power supply circuit malfunction

• Short to ground in the wiring harness between the following:

• MAIN 200 A fuse—Front body control module (FBCM) terminal 2A

• MAIN 200 A fuse—Front body control module (FBCM) terminal 1A

• MAIN 200 A fuse—Front body control module (FBCM) terminal 1B

• MAIN 200 A fuse—Front body control module (FBCM) terminal 3K

• MAIN 200 A fuse—Front body control module (FBCM) terminal 3L

• ROOM 15 A fuse malfunction

• HAZARD 25 A fuse malfunction

• MAIN 200 A fuse malfunction

• Open circuit in wiring harness between the following terminals:

• Battery positive terminal—Front body control module (FBCM) terminal 2A

• Battery positive terminal—Front body control module (FBCM) terminal 1A

• Battery positive terminal—Front body control module (FBCM) terminal 1B

• Battery positive terminal—Front body control module (FBCM) terminal 3K

• Battery positive terminal—Front body control module (FBCM) terminal 3L

• 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)].)

• Switch the ignition ON (engine off or on) and wait for 5 s or more.

• 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 5.

2

• Switch the ignition off.

• Disconnect the negative battery cable.

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

• 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 4.

3

• Always reconnect all disconnected connectors.

• Reconnect the negative battery cable.

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

• Display the PID VPWR_B using the M-MDS.

  (See PID/DATA MONITOR INSPECTION [FRONT BODY CONTROL MODULE (FBCM)].)

• Is the voltage B+?

Yes

Go to the next step.

No

Inspect the ROOM 15A fuse, HAZARD 25 A fuse and MAIN 200 A fuse.

• If the fuse is burnt out:

• Refer to the wiring diagram and verify whether or not there is a common connector between the following:

• MAIN 200 A fuse—Front body control module (FBCM) terminal 2A

• MAIN 200 A fuse—Front body control module (FBCM) terminal 1A

• MAIN 200 A fuse—Front body control module (FBCM) terminal 1B

• MAIN 200 A fuse—Front body control module (FBCM) terminal 3K

• MAIN 200 A fuse—Front body control module (FBCM) terminal 3L

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.

• Replace the fuse.

• If the fuse is damaged:

• Replace the fuse.

• If the fuse is normal:

• Refer to the wiring diagram and verify whether or not there is a common connector between the following:

• Battery positive terminal—Front body control module (FBCM) terminal 2A

• Battery positive terminal—Front body control module (FBCM) terminal 1A

• Battery positive terminal—Front body control module (FBCM) terminal 1B

• Battery positive terminal—Front body control module (FBCM) terminal 3K

• Battery positive terminal—Front body control module (FBCM) terminal 3L

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.

4

• 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)].)

• Switch the ignition ON (engine off or on) and wait for 5 s or more.

• 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.

5

• 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.