Differential System (W/ Differential Lock) Inspection

Inspect the indicator light.

1. Check that the indicator light lights up for approximately 1 second when the ignition switch is turned to ON.
   

Inspect the differential lock operation.

1. Jack up the vehicle and start the engine.
   

2. Shift the transfer shift lever to the L position.
   

3. When the differential lock control switch is set to the ON position, the indicator light turns 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 gears.

4. When the differential 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 four wheel drive control ECU when switching the differential control switch with the speedometer registering approximately 8 km/h (5 mph) or more.
   

   Switch Position	Terminal	Specified Condition
   ON	3 (M1) to 2 (M2)	0.5 V or less (No change)

   Text in Illustration

   *a

   ECU Side

6. Return the differential lock control switch to OFF.
   

7. Stop the engine and lower the vehicle.
   

Inspect the system circuit with the connector disconnected.

1. Disconnect the connector from the four wheel drive control ECU and inspect the connector on the wire harness side as shown in the table.
   

   Standard Voltage

   Tester Connection	Trouble Part	Condition	Specified Condition
   3 (M1) - 2 (M2)	Rear differential lock actuator	-	Less than 100 Ω
   7 (GND) - Body ground	Body ground	-	Below 1 Ω
   10 (SPD) - Body ground	Speed sensor	Vehicle moves slowly	1 pulse generation per 40 cm (15.75 in.)
   5 (IG) - Body ground	Differential fuse	Ignition switch ON	10 to 14 V
   1 (RLP) - Body ground	Rear differential lock indicator switch	Ignition switch ON with indicator light ON	About 0 V
   		Ignition switch ON with indicator light OFF	10 to 14 V
   8 (4WD) - Body ground	L position switch	Ignition switch ON with transfer shift lever not in L	About 0 V
   		Ignition switch ON with transfer shift lever in L	10 to 14 V
   4 (R) - Body ground	Differential lock control switch	Ignition switch ON with differential lock control switch ON	10 to 14 V
   		Ignition switch ON with differential lock control switch OFF	About 0 V

   HINT:

   If the result is not as specified, check and repair or replace the trouble part shown in the table above.

Inspect the system circuit with the connector connected.

1. Turn the ignition switch to ON.
   

2. Shift the transfer shift lever to the L position.
   

3. Using a voltmeter, measure the voltage when the differential lock control switch is in the position shown in the table.
   

   Standard Voltage

   Tester Connection	Switch Position	Specified Condition
   8 (4WD) - 7 (GND)	-	0.5 V or less
   1 (RLP) - 7 (GND)	ON*	0.5 V or less
   3 (M1) - 2 (M2)	OFF → ON	0.5 V or less → 10 to 14 V (approx. 1 sec.) → 0.5 V or less
   2 (M2) - 3 (M1)	ON → OFF

   Text in Illustration

   *a

   ECU Side

   HINT:

   *: The rear differential should be locked mechanically.

   1. If the result is not as specified, replace the ECU.
      

4. Install the ECU.
   

Inspect the relay operation.

1. Jack up the vehicle.
   

2. Use a heater main relay and connect it as shown below.
   

   NOTICE:

   Connect the terminals while being careful not to touch the neighboring terminals or metallic parts of the relay housing.





3. Rotate the tire and check that the differential lock has occurred.
   
   

   
   
   
   
   

   Text in Illustration

   *1	Heater Main Relay	-	-
   *a	Free → Lock	*b	Lock → Free

   1. If the operation is not as specified, replace the actuator.
      

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
3 - 4	OFF	10 kΩ or higher
	ON	Below 1 Ω

Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection	Switch Condition	Specified Condition
2 - 1	Pushed	Below 1 Ω
	Not pushed	100 kΩ or higher