Circuit Description

WARNING: This page is about a different variant/trim than selected.

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 forward clutch during Engine Idle Off mode. Engine Idle Off mode may also be referred to as PHT Engine Idle Off State. The Auxiliary Transmission Fluid Pump Relay receives voltage through the Battery Positive voltage circuit. The Auxiliary Transmission Fluid Pump attaches to the transmission valve body assembly. The Hybrid Control Module (HCM) controls the Auxiliary Transmission Fluid Pump by providing the ground path on the Auxiliary Transmission Fluid Pump relay control circuit. The PCM monitors the Transmission Fluid Pressure Switch (TFP) in order to determine the Auxiliary Transmission Fluid Pump operational status. When the Auxiliary Transmission Fluid Pump is commanded ON by the HCM during engine idle OFF mode, the TFP D4 switch remains closed, as there is no loss of line pressure. This indicates to the PCM that no gear selector position change has been detected.

When the HCM detects a TFP Switch signal C (D4) state change while in engine idle off mode, then DTC P2797 sets. DTC P2797 is a type B DTC.