LEMON Manuals: Even more car manuals for everyone
Home >> GMC >> 2003 >> Safari Van Cargo, AWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 68 (Automatic Transmission Diagnosis - 4L80-E (Gasoline)) >> Diagnostic Tests >> DTC P0748: Pc Solenoid Circuit - Electrical Malfunction >> Circuit Description

Circuit Description

WARNING: This page does not describe the selected car, but rather 12 other vehicles, including the 2002 GMC Savana Special, 2002 GMC Savana Camper Special, 2002 GMC Savana, 2002 Chevrolet RV Cutaway, and 2002 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

The Pressure Control (PC) solenoid valve is a PCM controlled device that regulates the transmission line pressure. The PCM compares TP sensor voltage, engine RPM, and other inputs to determine the appropriate line pressure for a given load. The PCM regulates line pressure by applying a varying duty cycle to the PC solenoid valve based on the resistance of the solenoid, and the amperage needed to obtain optimum line pressure. The applied amperage varies from 0.1 amps for maximum line pressure to 1.1 amps for minimum line pressure.

If the PCM detects a PC duty cycle that exceeds 95 percent or less than 1.9 percent, then DTC P0748 sets. DTC P0748 is a type "C" DTC.