Diagnostic Aids

WARNING: This page is about a different car, the 2003 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

ABS only: If a right front wheel speed sensor circuit DTC if also set, diagnose that DTC first. An ABS DTC should also set with P0318 on an ABS vehicle. The rough road signal on an ABS vehicle is sent to the ECM from the EBTCM over the CAN link.

To locate an intermittent problem, use scan tool to monitor DTC P0318 LAST TEST while driving the vehicle in the conditions listed under DTC parameters. A change from PASSED to FAILED indicates an error is occurring.

Another way to locate an intermittent problem is to backprobe White wire at the wheel speed conditioner module to verify the integrity of the signal to the ECM. Twelve volts should be on White wire with the ignition on and right front wheel not moving. As the wheel moves, the DVOM will fluctuate or read a lower voltage as the wheel spins. This indicates the wheel speed signal conditioner module is receiving the RFWSS signal and is momentarily grounding White wire. Lifting the vehicle and allowing the engine to drive the wheels will allow easy rotation of the right front wheel.

The wheel speed conditioner module is located behind the left center console trim panel (left side of gear shift).

Right front wheel speed sensor resistance: l-2 k/ohms.