Description

Communication error with electrical supply unit (ESU)

Detection condition

• BCM could not receive the signals from the electrical supply unit (ESU) for 5 s or more with the ignition switched ON (engine off or on).

Fail-safe

Exterior lighting system

• Turn the TNS (parking lights) and headlights LO on, and turn off other exterior light controls.

Possible cause

• Electrical supply unit (ESU) connector or terminal malfunction

• BCM connector or terminal malfunction

• Short to ground in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y

• Short to power supply in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y

• Open circuit in wiring harness between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y

• Electrical supply unit (ESU) malfunction

• BCM malfunction

Step

Inspection

Action

1

• Clear the DTC for the BCM using the M-MDS.

  (See CLEARING DTC [BCM].)

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

• Retrieve the BCM DTCs using the M-MDS.

  (See DTC INSPECTION [BCM].)

• Is the same DTC displayed?

Yes

Go to the next step.

No

Go to Step 9.

2

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Disconnect the electrical supply unit (ESU) 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 8.

3

• Disconnect the BCM 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 8.

4

• Verify that the electrical supply unit (ESU) and BCM connectors are disconnected.

• Inspect for continuity between BCM terminal 2Y (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 electrical supply unit (ESU) terminal 2I and BCM terminal 2Y.

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 8.

No

Go to the next step.

5

• Verify that the electrical supply unit (ESU) and BCM connectors are disconnected.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Switch the ignition ON (engine off or on).

• Measure the voltage at the BCM terminal 2Y (wiring harness-side).

• Is the voltage 0 V?

Yes

Go to the next step.

No

Refer to the wiring diagram and verify whether or not there is a common connector between electrical supply unit (ESU) terminal 2I and BCM terminal 2Y.

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 Step 8.

6

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Verify that the electrical supply unit (ESU) and BCM connectors are disconnected.

• Inspect the wiring harness for continuity between electrical supply unit (ESU) terminal 2I (wiring harness-side) and BCM terminal 2Y (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 electrical supply unit (ESU) terminal 2I and BCM terminal 2Y.

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 8.

7

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the BCM using the M-MDS.

  (See CLEARING DTC [BCM].)

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

• Retrieve the BCM DTCs using the M-MDS.

  (See DTC INSPECTION [BCM].)

• Is the same DTC displayed?

Yes

Replace the electrical supply unit (ESU), then go to the next step.

(See ELECTRICAL SUPPLY UNIT (ESU) REMOVAL/INSTALLATION.)

No

Go to Step 9.

8

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the BCM using the M-MDS.

  (See CLEARING DTC [BCM].)

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

• Retrieve the BCM DTCs using the M-MDS.

  (See DTC INSPECTION [BCM].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the BCM.

  (See BODY CONTROL MODULE (BCM) REMOVAL/INSTALLATION.)

Go to the next step.

No

Go to the next step.

9

• Are any other DTCs displayed?

Yes

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

(See DTC TABLE [BCM].)

No

DTC troubleshooting completed.