Transfer Case: Testing and Inspection

GENERAL NOTES:
A problem with the transfer case may be caused by the engine, the driving conditions, the transfer case itself, or the electrical control system. When troubleshooting, therefore, begin with the points that can be inspected quickly and easily. The recommended troubleshooting sequence is described below.




Self-diagnostic Function:
Inspection Check the warning alarm for operation.




Note: There is no memory in the 4WD control unit. When the ignition switch is turned OFF, the warning alarm is canceled unless the problem exists when the Ignition is again turned ON.




Electrical Signal Inspection:
Check the signals to/from the 4WD control unit.






System Operation Inspection:
Check operation of the Multi-Mode 4WD system.








Symptom Troubleshooting:
Check the Multi-Mode 4WD system for malfunctions.






QUICK DIAGNOSIS CHART

The quick diagnosis chart shows problems and the components that may be the cause.

1. Problems indicated by "X" in the Exclusion column may be normal operation.

2. The numbers in the chart indicate the order of inspection for easy detection of malfunctions.






SELF-DIAGNOSTIC FUNCTION INSPECTION






FAIL MODE FUNCTION:
The warning alarm will sound as shown if a malfunction occurs in the change motor or electrical circuit. Inspect the change motor and circuit, repair or replace as necessary.






Note: While in fail mode, the warning alarm (same as above) will sound each time the 4WD/2WD shift switch or center differential lock switch is activated. Fail mode function is canceled when the ignition switch is turned OFF. If a malfunction of either of the position switches occurs in the change motor while it is operating, the 4WD control unit sets the 2WD mode. If a malfunction of either limit switches occurs while shifting, the 4WD control unit sets the motor stop position.





CAUTION MODE FUNCTION:
The caution alarm will sound as shown if the 4WD/2WD switch is activated while driving in 4WD (Locked) mode. The proper sequence is to tirst turn oft the center differential lock switch to set 4WD (Free) mode, then activate the 4WD/2WD shift switch to set 2WD mode.






ELECTRICAL SIGNAL INSPECTION:
Check the electrical signals to/from the 4WD control unit.




























SYSTEM OPERATION INSPECTION 2W0 TO 4WD (FREE) MODE SHIFT

Note:
Jack up the vehicle and support it with safety stands. Place the transmission in NEUTRAL. Start the engine and let it idle. Verify that the center differential lock switch Is in OFF position. Verify that the CENTER DIFF. LOCK indicator lamp Is OFF. Verify that the 4W0 Indicator lamp is OFF.






















4WD (FREE) TO 2W0 MODE SHIFT

Note: Jack up the vehicle and support it with safety stands. Place the transmission in NEUTRAL. Start the engine and let it idle. Verify that the center differential lock switch is in OFF position. Verify that the CENTER DIFF. LOCK indicator lamp is OFF. Verify that the 4WD indicator lamp is ON.

























4WD (FREE) TO 4WD (LOCKED) MODE SHIFT


Note:

Jack up the vehicle and support it with safety stands. Place the transmission in NEUTRAL. Start the engine and let it idle. Verify that the center differential lock switch Is In OFF position. Verify that the CENTER DIFF. LOCK indicator lamp is OFF. Verify that the 4WD indicator lamp is ON.






4WD (LOCKED) TO 4WD (FREE) MODE SHIFT

Note: Jack up the vehicle and support it with safety stands. Place the transmission in NEUTRAL. Start the engine and let it idle. Verify that the center differential lock switch is in ON position. Verify that the CENTER DIFF. LOCK indicator lamp is ON. Verify that the 4WD indicator lamp is ON.































2WD TO 4WD (LOCKED) MODE SHIFT

Note:

Jack up the vehicle and support it with safety stands. Place the transmission in NEUTRAL. Start the engine and let it idle. Verify that the center differential lock switch is in OFF position. Verify that the CENTER DIFF. LOCK indicator lamp is OFF. Verify that the 4WD indicator lamp is OFF.