Refer to "53.Driveline Control 3A.Troubleshooting(4WD models) diagnostic system check-transfer case controls".
1) Connect the scan tool.
2) Turn OFF the ignition switch for 30 seconds or more.
3) Start the engine.
4) Drive the vehicle in 2H, 4H, and 4L modes respectively.
5) Observe the DTC information with a scan tool. Is a DTC set?
Yes
Go to the applicable DTC diagnosis.
No
=>Go to 4WD switch 2H signal input check.
1) Turn OFF the ignition switch.
2) Disconnect the 4WD switch harness connector (B56).
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
3) Turn ON the ignition switch.
4) Observe the Mode-Switch 2H-port Status parameter on the scan tool. Does the Mode-Switch 2H-port Status parameter show ON?
Yes
=>Go to Inspection for short circuit in 4WD switch 2H signal circuit.
No
=>Go to 4WD switch 4H signal input check.
1) Observe the Mode-Switch 4H-port Status parameter on the scan tool. Does the Mode-Switch 4H-port Status parameter show ON?
Yes
=>Go to Inspection for short circuit in 4WD switch 4H signal circuit.
No
=>Go to 4WD switch signal circuit resistance check.
1) Turn OFF the ignition switch.
2) Disconnect the TCCM harness connector (C15).
3) Measure the resistance between the 2H signal circuit and 4H signal circuit of the 4WD switch harness connector (pins 2 and 5 of B56). Is the resistance more than or equal to the specified value?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Value: 10 MΩ
Yes
=>Go to 4WD switch harness connector inspection.
No
=>Go to Inspection for short circuit in 4WD switch signal circuit.
1) Turn OFF the ignition switch.
2) Disconnect the TCCM harness connector (C15).
3) Inspect the 2H signal circuit between the TCCM (pin 24 of C15) and the 4WD switch (pin 5 of B56) for a short to ground. Is the result normal?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to TCCM harness connector inspection.
No
Repair the circuit as necessary.
1) Turn OFF the ignition switch.
2) Disconnect the TCCM harness connector (C15).
3) Inspect the 4H signal circuit between the TCCM (pin 20 of C15) and the 4WD switch (pin 2 of B56) for a short to ground. Is the result normal?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to TCCM harness connector inspection.
No
Repair the circuit as necessary.
1) Inspect the 2H signal circuit and 4H signal circuit between the TCCM (pins 20 and 24 of C15) and the 4WD switch (pins 2 and 5 of B56) for a short circuit. Is the result normal?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to TCCM harness connector inspection.
No
Repair the circuit as necessary.
1) Inspect for poor connections at the 4WD switch harness connector (pins 2 and 5 of B56). Is the connection status normal?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
=>Go to 4WD switch inspection.
No
Repair the connections as necessary.
1) Remove the 4WD switch.
Refer to "9.Body, Cab, Accessories 9C.Electrical Control, Entertainment 4WD switch removal".
2) Inspect the 4WD switch. Is the result normal?
Refer to "9.Body, Cab, Accessories 9C.Electrical Control, Entertainment 4WD switch inspection".
Yes
No
Replace the 4WD switch.
Refer to "9.Body, Cab, Accessories 9C.Electrical Control, Entertainment 4WD switch removal".
Refer to "9.Body, Cab, Accessories 9C.Electrical Control, Entertainment 4WD switch installation".
1) Inspect for poor connections at the TCCM harness connector (pins 20 and 24 of C15). Is the connection status normal?
Refer to "LHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Refer to "RHD 4WD" in the ETM (wiring diagram). (Open using the ETM viewer.).
Yes
No
Repair the connections as necessary.
Note
Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control TCCM removal".
Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control TCCM installation".
Refer to "3.Driveline, Axle 3Z.Driveline, Axle Electrical Control TCCM setting".
Procedure completion
1) Turn OFF the ignition switch for 30 seconds or more.
2) Turn ON the ignition switch.
3) Drive the vehicle in 2H, 4H, and 4L modes respectively.
4) Check the illumination status of the 4WD indicator light and 4WD low indicator light.