Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Center Diff. Lock System: Inspection: Notes
- INSPECT H4 (Differential lock "FREE") <=> H4 (Differential lock "LOCK") SHIFT
- Start the engine, and make sure that the differential lock switch is in "OFF" position.
- Operate the transfer shift lever to "H4" position.
- Check that the center diff. lock indicator light comes on after pressing the differential lock switch for 2 seconds.
Check that the center diff. lock indicator light goes off after pressing the differential lock switch for 2 seconds.
- INSPECT L4 (Differential lock "FREE") <=> L4 (Differential lock "LOCK") SHIFT
- Start the engine, and make sure that the differential lock switch is in "OFF" position.
- Operate the transfer shift lever to "L4" position.
- Check that the center diff. lock indicator light comes on after pressing the differential lock switch for 2 seconds.
Check that the center diff. lock indicator light goes off after pressing the differential lock switch for 2 seconds.
- INSPECT CENTER DIFFERENTIAL LOCK SWITCH CONTINUITY
- Remove the instrument panel finish lower panel sub-assy.
- Remove the differential lock switch from the instrument panel finish lower sub-assy.
- Inspect the continuity between the each terminal.TESTER CONNECTION AND SPECIFIED CONDITION
Switch position Tester connection Specified condition OFF +B (3) <=> GND (4) No continuity Hold ON +B (3) <=> GND (4) Continuity Illumination ILL+ (1) <=>ILL- (2) Continuity If continuity is not as specified, replace the differential lock switch or bulb.
- INSPECT ACTUATOR NOTE: Inspect the actuator while overhauling the transfer or as a unit.
- Turn the ignition switch OFF and set the parking brake.
- Using a rigid rack, jack up the vehicle so that the 4 wheels do not touch on the ground.
- Turn the ignition switch ON and check that the front propeller shaft free or lock when switching the center differential lock.CENTER DIFFERENTIAL LOCK SWITCH POSITION
Center differential lock switch Condition of front propeller shaft Off (center def. free) Possible to rotate On (center def. lock) Impossible to rotate HINT:
- When the transfer gear is off the position, shift fork of the actuator could not operate.
- When switching is impossible, jack down the vehicle to move it back and forth, and then check it again.
- Turn the ignition switch to ON.
- Check the operating sound produced by center differential lock switch operation.
If the operating sound cannot be heard, check the four wheel drive control ECU and the wire harness in the next step. When the wire harness and four wheel drive control ECU is normal, replace the actuator.
- INSPECT FOUR WHEEL DRIVE CONTROL ECU
- Connect the wire harness side connector to the four wheel drive control ECU and inspect wire harness side connector from the back side, as shown.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.