1) Connect the scan tool.
2) Check whether the scan tool powers up. Does the scan tool power up?
Yes
=>Go to Rear differential lock 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".
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
The system is normal.
No
1) Inspect for poor connections at the DLC (pins 6 and 14 of C19). Is the connection status normal?
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to Rear differential lock control unit harness connector inspection.
No
Repair the connections as necessary.
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
No
Repair the connections as necessary.
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.
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).
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
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).
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.
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.
No
Repair the circuit as necessary.
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 DLC (pins 6 and 14 of C19) for the following. Is the result normal?
Refer to "LHD Controller Area Network (Except Central Gateway C/U)" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD Controller Area Network (Except Central Gateway C/U)" 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.
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) 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.