P0748

Diagnostic Chart:

Schematic:

The Transaxle Control Module (TCM) uses the Pressure Control (PC) solenoid valve in order to regulate the transaxle line pressure. The PC solenoid valve consists of an electrical connector, a coil, an armature, a regulating spring, and a poppet valve. The PC solenoid valve is attached to the upper control body. The TCM compares TP voltage, engine speed, fluid temperature, gear states, and other inputs in order to determine the line pressure appropriate for a given load. The TCM regulates the pressure by applying a varying current to the PC solenoid valve. The applied current varies from 0.1 amps for maximum line pressure to 1.1 amps for minimum line pressure. The TCM then monitors the current at the return line. when the TCM detects a continuous open or short to ground in the PC solenoid valve circuit DTC P0748 sets. DTC P0748 is a type C DTC.

DTC PARAMETERS
DTC P0748 will set if PC actual current differs from PC command current by more than 0.16 amps and the following conditions have been met:
- Ignition voltage is between 8 and 18 volts
- Engine is running

DIAGNOSTIC AIDS
Inspect the wiring at the PCM, the transmission connector and the PC Sol. valve connector for the following conditions:
- A bent terminal
- A backed out terminal
- A damaged terminal
- Poor terminal tension
- A chafed wire
- A broken wire inside the insulation
- Moisture intrusion
- Corrosion
- When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
- Extended engine ranking with a weak battery could set DTC P0748.