Differential Lock: Testing and Inspection
ON-VEHICLE INSPECTION1. INSPECT DIFFERENTIAL LOCK SYSTEM
a. Inspect the indicator light.
Check that the indicator light lights up for approximately 1 second when the ignition switch is turned ON.
b. Inspect the differential lock operation.
1. Jack up the vehicle then start the engine.
2. Shift the transfer shift lever to L position.
3. When the diff. lock control switch is set to the RR position, the indicator light is turned on.
Differential lock is applied to the rear wheel at this time.
HINT: If the gears of the differential lock system are not meshed, the indicator light remains blinking, so rotate the tires to mesh the gear.
4. When the diff. lock control switch is at the OFF position, the indicator light goes off.
Differential lock is released for the rear wheel at this time.
5. Check the voltage between the terminals of the rear diff. lock control ECU when switching the diff. lock control switch with the speedometer, registering approximately 8 km/h (5 mph) or more.
6. Return the diff - lock control switch to OFF.
7. Stop the engine and lower the vehicle.
2. INSPECT DIFF. LOCK SYSTEM CIRCUIT
a. Inspect the battery positive voltage.
Battery positive voltage: 10 - 14 V
b. Inspect the system circuit with the connector disconnected.
Disconnect the connector from the rear diff. lock control ECU and inspect the connector on the wire harness side, as shown in the table.
HINT: If the circuit is not as specified value, check and repair or replace the trouble part shown in the table above.
c. Inspect the system circuit with the connector connected.
1. Turn the ignition switch to the ON position.
2. Shift the transfer shift lever to L position.
3. Using a voltmeter, measure the voltage when the differential lock control switch is in the position, as shown in the table.
*: The rear differential should be locked mechanically.
If the circuit is not as specified value, replace the ECU.
4. Install the ECU in place.
3. INSPECT DIFF. LOCK COMPONENTS
a. Inspect the relay operation.
1. Jack up the vehicle.
2. Use a heater main relay and connect it, as shown.
NOTICE: Connect the terminals being careful not to touch the neighboring terminals or metallic parts of the relay housing.
3. Rotate the tire and check that differential lock has occurred.
If operation is not as specified, replace the actuator.
b. Inspect the diff. lock control switch continuity.
Inspect the switch continuity between terminal 1 to terminal
HINT: If continuity dose not exist, replace the switch.
c. Inspect the diff. lock indicator switch.
1. Check that continuity between exists terminals when the switch is pushed (differential connected position).
2. Check that no continuity exists when the switch is free (differential disconnected position).
HINT: If operation is not as specified, replace the switch.
d. Inspect the L position switch.
e. Inspect the vehicle speed sensor.