Description

Communication error with start stop unit

Detection condition

• Rear body control module (RBCM) detects a communication error with the start stop unit for 10 times continuously.

Fail-safe function

Not applicable

Possible cause

• Start stop unit connector or terminal malfunction

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

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

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

• Start stop unit malfunction

• Rear body control module (RBCM) malfunction

Step

Inspection

Action

1

• Clear the DTC for the rear body control module (RBCM) using the M-MDS.

  (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].)

• Retrieve the rear body control module (RBCM) DTCs using the M-MDS.

  (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].)

• Is the same DTC displayed?

Yes

Go to the next step.

No

Go to Step 8.

2

• Switch the ignition off.

• Disconnect the negative battery cable.

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

• 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 7.

3

• 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 7.

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 body ground.

• Is there continuity?

Yes

Refer to the wiring diagram and verify whether or not there is a common connector between rear body control module (RBCM) terminal 3B and start stop unit terminal 1Q.

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 7.

No

Go to the next step.

5

• 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 start stop unit terminal 1Q (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 body control module (RBCM) terminal 3B and start stop unit terminal 1Q.

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 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 rear body control module (RBCM) using the M-MDS.

  (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].)

• Retrieve the rear body control module (RBCM) DTCs using the M-MDS.

  (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].)

• Is the same DTC displayed?

Yes

Replace the start stop unit, then go to the next step.

(See START STOP UNIT REMOVAL/INSTALLATION.)

No

Go to Step 8.

7

• 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 rear body control module (RBCM) using the M-MDS.

  (See CLEARING DTC [REAR BODY CONTROL MODULE (RBCM)].)

• Retrieve the rear body control module (RBCM) DTCs using the M-MDS.

  (See DTC INSPECTION [REAR BODY CONTROL MODULE (RBCM)].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the rear body control module (RBCM).

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

Go to the next step.

No

Go to the next step.

8

• Are any other DTCs displayed?

Yes

Repair or replace the malfunctioning part according to the applicable DTC troubleshooting.

(See DTC TABLE [REAR BODY CONTROL MODULE (RBCM)].)

No

DTC troubleshooting completed.