Circuit Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 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 powertrain control module (PCM) or the transmission control module (TCM) controls the actuator with a negative duty cycle. The actuator controls the fluid supply to the pump inlet in the rear drive assembly. When the actuator is commanded OFF, the PCM/TCM detects high voltage. When the actuator is commanded ON, the PCM/TCM detects 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.