1) Connect the scan tool.
2) Lift up the vehicle.
3) Turn OFF the ignition switch for 30 seconds or more.
4) Start the engine.
5) Turn OFF the rear differential lock switch.
6) Operate the vehicle.
7) Observe the EHCU DTC information with a scan tool. Is a DTC related to the rear wheel speed sensor set?
Yes
Go to the applicable DTC diagnosis.
No
=>Go to Differential Lock Status parameter check.
1) Turn OFF the rear differential lock switch.
2) Check whether the Differential Lock Status parameter shows Unlock on the scan tool while operating the vehicle.
3) Operate the vehicle with the following conditions met.
4WD models
2WD models
4) Check whether the Differential Lock Status parameter shows Lock on the scan tool. Does the Differential Lock Status parameter switch according to the driving conditions?
Yes
=>Go to Wheel Speed parameter check.
No
=>Go to Differential lock position switch signal input check.
1) Operate the vehicle with the following conditions met.
4WD models
2WD models
2) Observe the Rear Right Wheel Speed and Rear Left Wheel Speed parameters on the scan tool. Do both parameters show the same speed?
Yes
Go to Intermittent conditions of rear differential lock control system.
Refer to "204.Driveline, Axle 17D.Symptom intermittent conditions of differential lock control system".
No
Refer to the EHCU DTC list and inspect the rear wheel speed sensor circuit.
Refer to "54.Brake Control 4A.Troubleshooting(ABS/ESC) DTC List".
1) Turn OFF the ignition switch.
2) Disconnect the differential lock position switch harness connector (R38).
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.).
3) Turn ON the ignition switch.
4) Observe the Differential Lock Status parameter on the scan tool. Does the Differential Lock Status parameter show Unlock?
Yes
=>Go to Differential lock position switch inspection.
No
=>Go to Inspection for short to ground in differential lock position switch signal circuit.
1) Turn OFF the ignition switch.
2) Disconnect the rear differential lock control unit harness connector (C57).
3) Inspect the signal circuit between the rear differential lock control unit (pin 13 of C57) and the differential lock position switch (pin 1 of R38) for a short to ground or a short to the low reference circuit. 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
=>Go to Rear differential lock control unit replacement.
No
Repair the circuit as necessary.
1) Visually inspect the differential lock position switch for the following. Is the result normal?
2) Remove the differential lock position switch.
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) removal".
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) disassembly".
3) Visually inspect the rod of the differential lock position switch for smooth movement. Is the result normal?
4) Inspect for continuity between the connector terminals with a DMM while pushing and releasing the rod of the differential lock position switch with your fingers. Is the result normal?
The rod is pressed: No continuity
The rod is released: Continuity exists
5) Are all of the results normal?
Yes
Inspect the position plate installed to the differential cage, and repair or replace as necessary.
No
Replace the differential lock position switch.
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) removal".
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) disassembly".
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) inspection".
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) reassembly".
Refer to "3.Driveline, Axle 3B.Differentials rear final drive (φ220 mm { 8.66 in })(differential lock) installation".
Note
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
1) Securely connect all of the disconnected harness connectors.
2) Clear the DTC with a scan tool.
3) Turn OFF the ignition switch for 30 seconds or more.
4) Start the engine.
5) Turn OFF the rear differential lock switch.
6) Operate the vehicle.
7) Observe the DTC information with a scan tool.