Lost communication with the rear differential lock control unit (models with radar sensor/ stereo camera) (Differential Lock)

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 Rear differential lock control unit communication verification.

No

Go to Lost communication with the rear differential lock control unit (models without radar sensor).

Refer to "53.Driveline Control 3A.Troubleshooting(Differential Lock) lost communication with the rear differential lock control unit (models without radar sensor and stereo camera)".

3. Rear differential lock control unit communication verification

1) Verify that communication can be established with the rear differential lock control unit using the scan tool. Can communication with the rear differential lock control unit be established?

Yes

=>Go to Powertrain CAN communication circuit communication verification.

No

=>Go to Rear differential lock control unit harness connector inspection.

4. Powertrain 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?

  • ECM
  • TCCM
  • TCM
  • Battery sensor

Yes

The system is normal.

No

Go to Powertrain CAN communication circuit inspection.

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

5. Rear differential lock control unit harness connector inspection

1) Inspect for poor connections at the rear differential lock control unit harness connector (pins 1 and 9 of C57). Is the connection status normal?

Refer to "LHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Differential Lock" 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?

  • DIFF LOCK 10A fuse
  • IG2:ELEC IG2 10A fuse

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 rear differential lock control unit harness connector (C57).

3) Connect a test lamp between the battery power supply circuit of the rear differential lock control unit harness connector (pin 10 of C57) and the body ground. Does the test lamp illuminate?

Refer to "LHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Differential Lock" 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 DIFF LOCK 10A fuse and the rear differential lock control unit (pin 10 of C57).

=>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 rear differential lock control unit harness connector (pin 2 of C57) and the body ground. Does the test lamp illuminate?

Refer to "LHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Differential Lock" 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 ignition power supply circuit between the IG2:ELEC IG2 10A fuse and the rear differential lock control unit (pin 2 of C57).

=>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 rear differential lock control unit harness connector (pins 10 and 15 of C57). Does the test lamp illuminate?

Refer to "LHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

=>Go to Inspection for open circuit and short circuit in Powertrain 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 rear differential lock control unit (pin 15 of C57) and the body ground for an open circuit or high resistance. Is the result normal?

Refer to "LHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Refer to "RHD Differential Lock" in the ETM (wiring diagram). (Open using the ETM viewer.).

Yes

Repair corrosion and tightening of the rear differential lock 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 Powertrain CAN communication circuit

1) Inspect the CAN Low circuit and CAN High circuit between the rear differential lock control unit (pins 1 and 9 of C57) and the central gateway control unit (pins 5 and 6 of B41) for the following. Is the result normal?

  • Open circuit
  • High resistance
  • Short together between CAN communication circuits

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 Rear differential lock control unit replacement.

No

Repair the circuit as necessary.

=>Go to Repair verification.

12. Rear differential lock control unit replacement

Note

  • Perform programming after replacing the rear differential lock control unit.

Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control rear differential lock control unit removal".

Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control rear differential lock control unit installation".

Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control rear differential lock 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 rear differential lock control unit using the scan tool. Can communication with the rear differential lock control unit be established?

Yes

The system is normal.

No

=>Go to Rear differential lock control unit harness connector inspection.