Description

Error signal received from BCM

Detection condition

• Any of the following conditions is met with the ignition switched ON (engine off or on):

• The electrical supply unit (ESU) received a headlight LO on request signal error signal from the BCM for 2 s or more.

• The electrical supply unit (ESU) received a headlight HI on request signal error signal from the BCM for 2 s or more.

• The electrical supply unit (ESU) detected a mismatch in the following signal combinations received from the BCM for 2 s or more.

• Headlight variation information signal

• Headlight LO on request signal

• The electrical supply unit (ESU) detected a mismatch in the following signal combinations received from the BCM for 2 s or more.

• Headlight variation information signal

• Headlight HI on request signal

Fail-safe

Not applicable

Possible cause

• DTCs are stored in the BCM.

• BCM connector or terminal malfunction

• Electrical supply unit (ESU) connector or terminal malfunction

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

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

• BCM malfunction

• Electrical supply unit (ESU) malfunction

Step

Inspection

Action

1

• Retrieve the BCM DTCs using the M-MDS.

  (See DTC INSPECTION [BCM].)

• Are any DTCs displayed?

Yes

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

(See DTC TABLE [BCM].)

No

Go to the next step.

2

• Switch the ignition off.

• Disconnect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• 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 7.

3

• 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 7.

4

• Verify that the BCM and electrical supply unit (ESU) 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 BCM terminal 2Y and electrical supply unit (ESU) terminal 2I.

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 BCM and electrical supply unit (ESU) 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 BCM terminal 2Y and electrical supply unit (ESU) terminal 2I.

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 7.

6

• Always reconnect all disconnected connectors.

• Connect the negative battery cable.

  (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION.)

• Clear the DTC for the electrical supply unit (ESU) using the M-MDS.

  (See CLEARING DTC [ELECTRICAL SUPPLY UNIT (ESU)].)

• Switch the ignition ON (engine off or on) and wait for 2 s or more.

• Retrieve the electrical supply unit (ESU) DTCs using the M-MDS.

  (See DTC INSPECTION [ELECTRICAL SUPPLY UNIT (ESU)].)

• Is the same DTC displayed?

Yes

Replace the BCM, then go to the next step.

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

No

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 electrical supply unit (ESU) using the M-MDS.

  (See CLEARING DTC [ELECTRICAL SUPPLY UNIT (ESU)].)

• Switch the ignition ON (engine off or on) and wait for 2 s or more.

• Retrieve the electrical supply unit (ESU) DTCs using the M-MDS.

  (See DTC INSPECTION [ELECTRICAL SUPPLY UNIT (ESU)].)

• Is the same DTC displayed?

Yes

Repeat the inspection from Step 1.

• If the malfunction recurs, replace the electrical supply unit (ESU).

  (See ELECTRICAL SUPPLY UNIT (ESU) 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 [ELECTRICAL SUPPLY UNIT (ESU)].)

No

DTC troubleshooting completed.