Description

Communication error with rear body control module (RBCM)

Detection condition

• Start stop unit detects the communication error with rear body control module (RBCM) 10 times continuously.

Fail-safe function

Not applicable

Possible cause

• Rear body control module (RBCM) connector or terminal malfunction

• Start stop unit connector or terminal malfunction

• Short to ground in wiring harness between start stop unit terminal 1Q and rear body control module (RBCM) terminal 3B

• Open circuit in wiring harness between start stop unit terminal 1Q and rear body control module (RBCM) terminal 3B

• Rear body control module (RBCM) malfunction

• Start stop unit malfunction

Step

Inspection

Action

1

• Switch the ignition off.

• Disconnect the negative battery cable.

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

• Disconnect the rear body control module (RBCM) 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.

2

• Disconnect the start stop unit 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.

3

• Verify that the rear body control module (RBCM) and start stop unit connectors are disconnected.

• Inspect for continuity between rear body control module (RBCM) terminal 3B (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 start stop unit terminal 1Q and rear body control module (RBCM) terminal 3B.

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.

4

• Verify that the rear body control module (RBCM) and start stop unit connectors are disconnected.

• Inspect for continuity between start stop unit terminal 1Q (wiring harness-side) and rear body control module (RBCM) terminal 3B (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 start stop unit terminal 1Q and rear body control module (RBCM) terminal 3B.

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 Step 6.

5

• 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 start stop unit using the M-MDS.

  (See CLEARING DTC [START STOP UNIT].)

• Retrieve the start stop unit DTCs using the M-MDS.

  (See DTC INSPECTION [START STOP UNIT].)

• Is the same DTC displayed?

Yes

Replace the rear body control module (RBCM), then go to the next step.

(See REAR BODY CONTROL MODULE (RBCM) REMOVAL/INSTALLATION.)

No

Go to Step 7.

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 start stop unit using the M-MDS.

  (See CLEARING DTC [START STOP UNIT].)

• Retrieve the start stop unit DTCs using the M-MDS.

  (See DTC INSPECTION [START STOP UNIT].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the start stop unit.

  (See START STOP UNIT 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 [START STOP UNIT].)

No

DTC troubleshooting completed.