Checking the voltage on the sensors with the connector disconnected.
Voltage test for differential lock switch with connector connected.
General information
The rear differential lock system controls the movement of the lock-up clutch, which engages with the axle shaft and, by engaging with the differential cup, blocks the operation of the rear differential.
An electric drive is used to move the differential lock clutch. The electric drive is turned on and off by the signals of the electronic control unit, which receives signals from the rear differential lock switch located on the dashboard in the cabin, and from other switches and sensors. The drive motor is built into the differential lock mechanism.
Troubleshooting
Note:
- Make sure all wheel drive mode (4WD) included.
- When switching "free running" <-> "Differential lock" the indicator will flash if the gears of the lockup clutch are not engaged. If the shift occurs while the wheels are spinning, the differential locks and the indicator light stays on.
1. If the indicator does not light up:
- A) Check the fusible link.
- b) Check fuse "GAUGE" (Devices) and make sure there is no short circuit.
- V) Check the indicator lamp.
- G) Check for an open circuit or poor "grounding".
2. If the indicator does not light up (differential lock switch in position "RR"):
- A) Check fuse "DIFF" in the differential lock circuit and check that there is no short circuit.
- b) Check differential lock switch.
- V) Check differential lock control unit.
- G) Check for circuit damage or poor "grounding".
3. If the differential lock does not work:
- A) Check the differential lock switch.
- b) Check the differential lock actuator.
- V) Check differential lock control unit.
- G) Check the differential lock mechanism in the gearbox.
- d) Check for an open circuit or poor "grounding".
4. If the rear differential lock does not disengage when the vehicle speed exceeds 8 km/h:
- A) Check the speed sensor in the instrument cluster.
- b) Check differential lock control unit.
- V) Check for an open circuit or poor "grounding".
Checking system operation
1. Checking the indicator.
A) Set the ignition switch to position "ON" (Included).
b) Check that the rear differential lock indicator illuminates for approximately 1 second.
2. Checking the operation of the rear differential lock mechanism.
Note: Set the shift lever to the position "N" (neutral).
A) Put the car on stands and start the engine.
b) Turn on all-wheel drive (press the button "H4").
V) Turn the differential lock switch to position "RR": The lock should engage and the rear differential lock indicator should illuminate.
Note: If the differential lock gears do not mesh, the indicator will flash until the wheels rotate to engage the gears.
G) Turn the differential lock switch to position "OFF" (Turned off): The rear differential lock should disengage and the indicator should turn off.
d) Check voltage between terminals 3 (M1) and 2 (M2) connector of the control unit for the rear differential lock system, when the differential lock switch is moved from the position "OFF" into position "RR", when the speedometer shows a speed of about 8 km/h or higher.
Voltage is 0.5 V or less.
e) Check that the indicator flashes when the rear wheel drive mode is engaged (2WD). In this case, the rear differential lock should be disabled.
h) Set the rear differential lock switch to "OFF".
And) Stop the engine and lower the car onto its wheels.
Checking the control unit
1. Disconnect the connector from the rear differential lock control unit and check the connector on the wire harness side. If the circuit parameters are out of specification, repair or replace the defective parts.
A) Check resistance between terminals 2 (M2) and 3 (M1). If the resistance exceeds the allowable value, then check the drive of the rear axle differential lock mechanism.
Resistance - less than 100 ohms
b) Check for continuity between terminal 7 (GND) and 'earth'.
V) Check continuity between terminal 10 (SPD) And "earth" when the vehicle is moving slowly. If the conductivity is different from normal, then check the speed sensor in the instrument cluster.
Conductivity - 1 pulse (0.4 m way)
G) Set the ignition switch to position "ON" (Included).
d) Check voltage between terminal 5 (IG) And "earth". If the voltage does not match the battery voltage, check the fuse "DIFF" (differential lock circuit).
e) Check the voltage on the sensors-switches according to the corresponding table.
and) Check the voltage at the terminals at various positions of the differential lock switch.
2. Make sure the battery voltage is normal.
Voltage - 10.0 - 14.5 V
3. Connect the connector to the rear differential lock system control unit and check the connector on the control unit side.
A) Turn the ignition switch to position "ON" (Included).
b) Turn on all-wheel drive (4WD).
V) Remove the rear differential lock control unit.
G) Using a voltmeter, measure the voltage at various positions of the differential lock switch (see corresponding table). If the circuit is out of specification, replace the rear differential lock control unit.
d) Reinstall the rear differential lock control unit.
Checking the operation of the locking mechanism drive relay
1. Put the car on stands.
2. Use a known-good main heater relay and wire it as shown.
3. Rotate the wheel and check for rear differential lock.
4. If there is no blocking operation of the rear differential, then replace the blocking mechanism drive.
Checking the differential lock switch
1. Check for continuity between terminals 1 (IN) and 4 (R) connector when the switch is in the position "OFF" (rear differential lock disabled).
2. Check for continuity between terminals 1 (IN) and 4 (R), when the switch is in position "RR" (rear differential lock engaged).
3. If conductivity between plugs of a socket differs from resulted above replace the switch of blocking of back differential.
Checking sensors
1. Checking the differential lock enable sensor
A) Check for continuity between the terminals when the sensor-switch is pressed (differential connection position).
b) Check for continuity between the terminals when the switch is released (differential release position).
V) Replace the switch switch if it does not work as described above.
2. Checking the all-wheel drive enable sensor and speed sensor (see section "Freewheel automatic locking system").