Circuit/System Description

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The auxiliary transmission fluid pump is an electrical device that is used with the auxiliary transmission fluid pump relay to maintain transmission fluid line pressure to the transmission during Engine Idle Off mode. The ECM monitors the transmission fluid pressure switch (TFP) to verify that the auxiliary transmission pump is maintaining the proper amount of pressure. The auxiliary transmission fluid pump attaches to the transmission side cover assembly. The auxiliary transmission fluid pump relay receives voltage through the battery positive voltage circuit. The starter generator control module (SGCM) controls the auxiliary pump by providing the ground path on the auxiliary pump relay control circuit sending power to the hybrid pump driver (HPD). The SGCM monitors all of the circuits of the auxiliary transmission fluid pump control circuits.