Operation CHARM: Car repair manuals for everyone.

Test B





Pinpoint Test B: The Vehicle Does Not Shift Between 4WD Auto and 4H Correctly

Normal Operation

With the key in the ON position, the 4x4 module (PCM) receives the operator's choice of four-wheel drive selection from the mode select. The 4x4 module (PCM) then controls the electric clutch and shift motor. If the transfer case is not responding to the operator's intentions, systematically check all inputs and outputs to the 4x4 module (PCM).

Possible Causes

- 4WD indicators
- transfer case
- 4x4 module (PCM)
- circuits:
- 359 (GY/RD)
- 779 (BN)
- 780 (DB)
- transfer case clutch
- ignition switch and/or circuitry
- CAN communication network
- instrument cluster (IC)


Pinpoint Test B1 - B5:





Pinpoint Test B6 - B10:





Pinpoint Test B11 - B14:





Pinpoint Test B15 - B18:





Pinpoint Test B19 & B20:





Pinpoint Test B21 & B22: