Lost communication with the headlight auto leveling control unit (models with radar sensor/ stereo camera) (Headlight Automatic Leveling Control)

1. Scan tool power-up check

1) Connect the scan tool.

2) Check whether the scan tool powers up. Does the scan tool power up?

Yes

=>Go to Central gateway control unit communication verification.

No

Go to Scan tool does not power up.

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 with DPD) Scan tool does not power up".

Refer to "51.Engine Control 1A.Troubleshooting(4JJ3 without DPD) Scan tool does not power up".

Refer to "51.Engine Control 1A.Troubleshooting(RZ4E-TC) Scan tool does not power up".

2. Central gateway control unit communication verification

1) Verify communication with the central gateway control unit using the scan tool. Can communication with the central gateway control unit be established?

Yes

Go to Intermittent conditions of lighting control system.

Refer to "224.Lighting Control 37D.Symptom(Headlight Automatic Leveling Control) intermittent conditions of lighting control system".

No

=>Go to Headlight auto leveling control unit communication verification.

3. Headlight auto leveling control unit communication verification

1) Verify that communication can be established with the headlight auto leveling control unit using a scan tool. Can communication with the headlight auto leveling control unit be established?

Yes

=>Go to Body CAN communication circuit communication verification.

No

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

4. Body CAN communication circuit communication verification

1) Verify that communication can be established with the following control modules using a scan tool. Can communication with all the control modules be established?

Yes

The system is normal.

No

Go to Body CAN communication circuit inspection.

Refer to "64.Body Control 10I.Troubleshooting(Central GateWay) body CAN communication circuit inspection".

5. Headlight auto leveling control unit harness connector inspection

1) Inspect for poor connections at the headlight auto leveling control unit harness connector (pins 15 and 16 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 Fuse inspection.

No

Repair the connections as necessary.

=>Go to Repair verification.

6. Fuse inspection

1) Inspect the following fuses. Is the result normal?

Yes

=>Go to Inspection for open circuit in battery power supply circuit.

No

Replace the fuse as necessary. If the fuse blows out again, repair the short to ground in the circuits relating to the fuse.

=>Go to Repair verification.

7. Inspection for open circuit in battery power supply circuit

1) Turn OFF the ignition switch.

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

3) Connect a test lamp between the battery power supply circuit of the headlight auto leveling control unit harness connector (pin 1 of C99) and the body ground. Does the test lamp illuminate?

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

Yes

=>Go to Inspection for open circuit in ignition power supply circuit.

No

Repair the open circuit or high resistance in the battery power supply circuit between the ELEC(+B) 10A fuse and the headlight auto leveling control unit (pin 1 of C99).

=>Go to Repair verification.

8. Inspection for open circuit in ignition power supply circuit

1) Turn ON the ignition switch.

2) Connect a test lamp between the ignition power supply circuit of the headlight auto leveling control unit harness connector (pin 3 of C99) and the body ground. Does the test lamp illuminate?

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

Yes

=>Go to Ground circuit check.

No

Repair the open circuit or high resistance in the battery power supply circuit between the H/LAMP LEVELING(IG2) 5A fuse and the headlight auto leveling control unit (pin 3 of C99).

=>Go to Repair verification.

9. Ground circuit check

1) Connect a test lamp between the battery power supply circuit and the ground circuit of the headlight auto leveling control unit harness connector (pins 1 and 2 of C99). Does the test lamp illuminate?

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

Yes

=>Go to Inspection for open circuit and short circuit in Body CAN communication circuit.

No

=>Go to Inspection for open circuit in ground circuit.

10. Inspection for open circuit in ground circuit

1) Inspect the ground circuit between the headlight auto leveling control unit (pin 2 of C99) and the body ground for an open circuit or high resistance. Is the result normal?

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

Yes

Repair corrosion and tightening of the headlight auto leveling control unit ground terminals.

=>Go to Repair verification.

No

Repair the circuit as necessary.

=>Go to Repair verification.

11. Inspection for open circuit and short circuit in Body CAN communication circuit

1) Inspect the CAN Low circuit and CAN High circuit between the headlight auto leveling control unit (pins 15 and 16 of C99) and the central gateway control unit (pins 3 and 4 of B41) for the following. Is the result normal?

Refer to "LHD Controller Area Network (Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 with DPD))" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Controller Area Network (Central Gateway C/U (4JJ3 without DPD, RZ4E))" 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.

12. 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.

13. Repair verification

1) Connect all of the removed fuses and harness connectors.

2) Turn OFF the ignition switch.

3) Turn ON the ignition switch.

4) Verify that communication can be established with the headlight auto leveling control unit using a scan tool. Can communication with the headlight auto leveling control unit be established?

Yes

The system is normal.

No

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