DTC B1037[12] (Flash Code 44) Leveling Power Supply "Circuit Short to Battery" (Headlight Automatic Leveling Control)

1. Headlight auto leveling system check

Refer to "65.Lighting Control 10J.Troubleshooting(Headlight Automatic Leveling Control) diagnostic system check-headlight auto leveling controls".

2. Current DTC check

1) Connect the scan tool.

2) Turn OFF the ignition switch.

3) Turn ON the ignition switch and wait for 5 seconds or more.

4) Perform initialization procedures of the vehicle height values to operate the headlight leveling actuators. Do the headlight leveling actuators operate?

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control headlight auto leveling control unit setting".

5) Observe the DTC information with a scan tool. Is a DTC set?

Yes

Go to the applicable DTC diagnosis.

No

=>Go to Headlight leveling actuator harness connector inspection.

3. Headlight leveling actuator harness connector inspection

1) Inspect for poor connections at the headlight leveling actuator harness connector (pins 1, 2, and 3 of C26, pins 1, 2, and 3 of C27). Is the connection status normal?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Headlight auto leveling control unit harness connector inspection.

No

Repair the connections as necessary.

=>Go to Repair verification.

4. Headlight auto leveling control unit harness connector inspection

1) Inspect for poor connections at the headlight auto leveling control unit harness connector (pins 6, 7, and 9 of C99). Is the connection status normal?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Headlight leveling actuator operation check.

No

Repair the connections as necessary.

=>Go to Repair verification.

5. Headlight leveling actuator operation check

1) Perform initialization procedures of the vehicle height values to operate the headlight leveling actuators. Do the headlight leveling actuators operate?

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control headlight auto leveling control unit setting".

Yes

Repair verification

No (The right headlight leveling actuator does not operate.)

=>Go to Right headlight leveling actuator power supply voltage check.

No (The left headlight leveling actuator does not operate.)

=>Go to Left headlight leveling actuator power supply voltage check.

6. Right headlight leveling actuator power supply voltage check

1) Turn OFF the ignition switch.

2) Disconnect the right headlight leveling actuator harness connector (C26).

3) Measure the voltage between the right headlight leveling actuator (pin 3 of C26) and the body ground with a DMM. Is the voltage more than or equal to the specified value?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Value: 2.27 V

=>Go to Inspection for short to power supply in right headlight leveling actuator power supply circuit.

No

=>Go to Headlight replacement.

7. Inspection for short to power supply in right headlight leveling actuator power supply circuit

1) Turn OFF the ignition switch.

2) Disconnect the headlight auto leveling control unit harness connector (C99).

3) Inspect the power supply circuit between the headlight auto leveling control unit (pin 6 of C99) and the right headlight leveling actuator (pin 3 of C26) for the following. Is the result normal?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Headlight auto leveling control unit replacement.

No

Repair the circuit as necessary.

=>Go to Repair verification.

8. Left headlight leveling actuator power supply voltage check

1) Turn OFF the ignition switch.

2) Disconnect the left headlight leveling actuator harness connector (C27).

3) Turn ON the ignition switch.

4) Measure the voltage between the power supply circuit and the ground circuit of the left headlight leveling actuator (pins 1 and 3 of C27) with a DMM. Is the voltage more than or equal to the specified value?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Value: 2.27 V

=>Go to Inspection for short to power supply in left headlight leveling actuator power supply circuit.

No

=>Go to Headlight replacement.

9. Inspection for short to power supply in left headlight leveling actuator power supply circuit

1) Turn OFF the ignition switch.

2) Disconnect the headlight auto leveling control unit harness connector (C99).

3) Inspect the power supply circuit between the headlight auto leveling control unit (pin 6 of C99) and the left headlight leveling actuator (pin 3 of C27) for the following. Is the result normal?

Refer to "LHD Headlight Leveling (Auto Leveling)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Headlight auto leveling control unit replacement.

No

Repair the circuit as necessary.

=>Go to Repair verification.

10. Headlight replacement

Refer to "9.Body, Cab, Accessories 9A.Lighting Systems headlight removal".

Refer to "9.Body, Cab, Accessories 9A.Lighting Systems headlight installation".

Procedure completion

=>Go to Repair verification.

11. Headlight auto leveling control unit replacement

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control headlight auto leveling control unit removal".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control headlight auto leveling control unit installation".

Refer to "9.Body, Cab, Accessories 9Z.Body, Cab, Accessories Electrical Control headlight auto leveling control unit setting".

Procedure completion

=>Go to Repair verification.

12. Repair verification

1) Reconnect all of the disconnected harness connectors.

2) Turn ON the ignition switch and wait for 5 seconds or more.

3) Observe the DTC information with a scan tool.