P0748

Circuit Description
The PCS is a PCM-Controlled device used to regulate transmission line pressure. The PCM compares TPS voltage, engine rpm, and other inputs to determine the line pressure appropriate for a given load. The PCM will regulate the pressure by applying a varying amperage to the PCS. The applied amperage can vary from 0.1 to 1 amp, and is monitored by the PCM.
This DTC detects a continuous open or short to ground in the PCS circuit or the PCS. This is a type "C" DTC.

Conditions For Setting The DTC
- Battery voltage is between 10 and 16 volts.
- The PCM detects that the different between commanded and actual current is 200 milliampere (mA) for over 1 second.

Action Taken When the DTC Sets
- The PCM will not illuminate the Malfunction Indicator Lamp (MIL).
- Maximum line pressure.
- The PCM will illuminate the CHECK TRANS Lamp.

Conditions For Clearing The DTC/CHECK TRANS Lamp
- The PCM will turn "off" the CHECK TRANS Lamp after three consecutive ignition cycles without a failure reported.
- The DTC can be cleared from PCM history by using a scan tool.
- The DTC will be cleared from memory when the vehicle has achieved 40 warmup cycles without a failure reported.
- The PCM will cancel the DTC default actions when the fault no longer exists and the ignition is cycled 'OFF
long enough to power down the PCM. A

Diagnostic Aids
- Inspect the wiring for poor electrical connection at the PCM and at the transmission 5-way connector. Look for possible bent, backed out, deformed or damaged terminals. Check for weak terminal tension as well. Also check for a chafed wire that could short to bare metal or other wiring. Inspect for a broken wire inside the insulation.
- When diagnosing for a possible intermittent short or open condition, move the wiring harness while observing test equipment for a change.

Test Description
The numbers below refer to the step numbers on the diagnostic chart:
2. This test checks the ability of the PCM to command the PCS.
3. This test checks the PCS and internal wiring harness for incorrect resistance.





DTC P0748 Pressure Control Solenoid (PCS) (Force Motor) Circuit Electrical