Differential Lock: Description and Operation

This system frees or locks the Front and Rear Differentials according to the position of the diff. lock control SW. The differential will lock only when the center diff. lock detection SW is ON and the vehicle speed is at 8 kph (5 mph) or less.

When the center diff. lock indicator SW is OFF, differential lock does not occur even if the diff. lock control SW is in RR position or FR.RR position.

When the Diff. Lock Control SW is switched from OFF position to RR position, current flows from the DIFF fuse through the Diff. Lock Control SW to TERMINAL 12 of the Diff. Lock ECU. If the limit SW on the lock side inside the rear diff. lock control motor is ON at this time, until the limit SW is turned OFF, current flows from the DIFF fuse to TERMINAL 8 of the diff. lock ECU --> TERMINAL 3 --> TERMINAL 3 of the rear diff. lock control motor --> TERMINAL 2 --> TERMINAL 1 of the diff. lock ECU --> TERMINAL 13 --> GROUND. This drives the rear diff. lock control motor and locks the rear differential. When the rear differential locks. the rear diff. lock position SW turns ON, lighting up the rear diff. lock indicator light in the combination meter.

When the diff. lock control SW is switched from RR position to FR.RR position, current flows from the DIFF fuse through the diff. lock control SW to TERMINAL 6 of the diff. lock ECU. If the limit SW on the lock side inside the front diff. lock control motor is on at this time. until the limit SW is turned OFF, current flows from the DIFF fuse to TERMINAL 8 of the diff. lock ECU --> TERMINAL 7 --> TERMINAL 3 of the front diff. lock control motor --> TERMINAL 2 --> TERMINAL 5 of the diff. lock ECU TERMINAL 13 --> GROUND. This drives the front diff. lock control motor and locks the front differential. When the front differential locks, the front diff. lock position SW turns ON, lighting up the front diff. lock indicator light in the combination meter.

When the diff. lock control SW is switched from FR.RR position to RR position, current to TERMINAL 6 of the diff. lock ECU is cut OFF. If the limit SW on the free side inside the front diff. lock control motor is ON at this time, until the limit SW is turned OFF, current flows from the Diff fuse to TERMINAL 8 of the diff. lock ECU --> TERMINAL 5 --> TERMINAL 2 of the front diff. lock control motor --> TERMINAL 3 --> TERMINAL 7 of the diff. lock ECU --> TERMINAL 13 --> GROUND. This drives the front diff. lock control motor and frees the front differential. This causes the front diff. lock position SW and the front diff. lock indicator light inside the combination meter to turn OFF.

When the diff. lock control SW is switched from RR position to OFF position, current to TERMINAL 12 of the diff. lock ECU is cut OFF. If the limit SW on the free side inside the rear diff. lock control motor is ON, until the limit SW is turned OFF, current flows from the DIFF fuse to TERMINAL 8 of the diff. lock ECU --> TERMINAL 1 --> TERMINAL 2 of the rear diff. lock control motor --> TERMINAL 3 --> TERMINAL 3 of the diff. lock ECU --> TERMINAL 13 --> GROUND. This drives the rear diff. lock control motor and frees the rear differential. When the rear differential is free, the rear diff. lock position SW and the rear diff. lock indicator light in the combination meter are turned OFF.


The Diff. Lock Indicator Light Flashes When:
^ The diff. lock control SW is switched to RR position or FR.RR position during differential lock prohibition conditions (vehicle speed above 8 kph (5 mph) or center diff. lock indicator SW OFF).
^ The diff. lock position SW is turned OFF during operation of the diff. lock control motor.