P0748

WITH 4L60-E AUTOMATIC TRANSMISSION

DTC P0748 Pressure Control Solenoid (PCS) Circuit:

Pressure Control Solenoid (PCS) Circuit Electrical:

CIRCUIT DESCRIPTION
The pressure control solenoid is a Vehicle Control Module-A (VCM-A) controlled device used to regulate transmission line pressure. The VCM-A compares Throttle Position (TP) voltage, engine RPM and other inputs to determine the line pressure appropriate for a given load. The VCM-A will regulate the pressure by applying a varying amperage to the pressure control solenoid. The applied amperage can vary from 0.1 to 1.1 amp and is monitored by the VCM-A. DTC Type (D).

DTC P0748 WILL SET WHEN
The return amperage varies greater than 0.16 amp from the commanded amperage, for at least two seconds.

ACTION TAKEN (VCM-A will default to)
Full line pressure will be applied causing harsh shifts. DTC P0748 will be stored in the VCM-A memory but will not turn "ON" the MIL (Malfunction Indicator Lamp).

DTC PO748 WILL CLEAR DEFAULT ACTION WHEN
The fault condition(s) no longer exist and the ignition switch is cycled "OFF" for five seconds, then "ON".

DTC PO748 WILL PASS WHEN
- VCM-A will report a "PASS" when return amp varies less than 0.16 amp and no shorts or opens are indicated.
- All enable criteria are met.

DTC CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.
1. This test checks the ability of the VCM-A to command the pressure control solenoid.
2. This test checks the wiring harness and the pressure control solenoid for incorrect resistance.

DIAGNOSTIC AIDS
Check for poor connections at VCM-A and at transmission connector.
If pressure readings differ greatly from the line pressure chart, refer to the C Charts. Refer to Computers and Control Systems. Testing and Inspection