Circuit Description

WARNING: This page is about a different car, the 2003 Pontiac Aztek and 2003 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

The differential clutch pump actuator check valve assembly is a pulse width modulated actuator mounted to the rear drive assembly. Ignition voltage is supplied to the clutch pump actuator check valve through a fused circuit. The PCM controls the actuator with a negative duty cycle. The actuator controls the supply fluid to the pump inlet in the rear drive assembly. When the actuator is commanded OFF, the PCM will detect a high voltage. When the actuator is commanded ON, the PCM will detect a low voltage. At engine start-up, the actuator is turned ON at 49-90 percent duty cycle for 3 seconds, then drops to 16-28 percent for holding.

Every 30 seconds, the duty cycle is ramped to 49-90 percent for 0.5 second, then back to 16-28 percent.

If the PCM detects a voltage on the axle actuator circuit that is outside of the calibrated limits then the all-wheel drive (AWD) disable lamp illuminates.