High or Low Line Pressure

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.

Checks	Cause
ECM Torque Related DTC's are set.	DTC's can cause the engine torque value used by the TCM to become invalid. When the engine torque is invalid, the TCM will command maximum line pressure to protect the transmission.
Oil Level	High or Low; correct as required
Pressure Regulator Valve (328) Springs (326, 327) Boost Valve (325)	Stuck
Pressure Control Solenoid (312)	Leak, damaged O-rings Loose connector, damaged pins Contaminated
Torque Signal Regulator Valve (309)	Stuck
Transmission Wiring Harness (11)	Loose connector at the vehicle harness Short
Pressure Switch Assembly	Loose connector Damaged or missing O-ring
Throttle Position Sensor	Damaged, sticking, disconnected An intermittent open or a shorted circuit
Oil Filter (85)	Clogged, broken, or loose
Oil Filter Seal (84)	Leaking
Cooler Lines	Clogged or restricted
Cooler Line Seals (49)	Leaking
Oil Pump (10)	Damaged, sticking, porous, or leaking
Oil Pump Drive Shaft (19)	Damaged
Pressure Relief Valve (214)	Damaged spring or missing ball
Transmission Case (1) Valve Body (18) Channel Plate (27)	Porosity, leaking circuits Flatness of machined surfaces