Test I: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 LOW Correctly
Pinpoint Test I: The Vehicle Does Not Shift Between 4X4 AUTO and 4X4 LOW CorrectlyRefer to Vehicle/Diagrams, Four-Wheel Drive (4WD) System for schematic and connector information.
Normal Operation
With the key in the ON position, the 4X4 control module receives the operator's choice of four wheel drive (4WD) selection from the mode select switch (MSS). The 4X4 control module then controls the electric clutch and transfer case shift motor. If the transfer case is not responding to the operator's intentions, systematically check all inputs and outputs to the 4X4 control module.
This pinpoint test is intended to diagnose the following:
^ Wiring, terminals or connectors
^ Fuses
^ 4X4 LOW indicator
^ 4X4 LOW LED
^ MSS
^ Transfer case
^ Transfer case shift motor
^ 4X4 control module
^ ABS module
^ High-speed controller area network (HS-CAN)