Code 73, Pressure Control Solenoid (Current Error): Notes

WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 1994 GMC Yukon, 1994 GMC Suburban, 1994 GMC Pickup, 1994 GMC Cab & Chassis, and 1994 GMC C3500 HD. However, it is still accessible from the selected car via links, so may be relevant.

NOTE: This flow chart requires the use of a bidirectional (Tech 1) scan tester.

The pressure control solenoid, is a PCM/TCM-controlled device used to regulate transmission line pressure. The PCM/TCM looks at TPS voltage, engine RPM and other inputs to determine appropriate line pressure for a given load, then regulates the pressure by applying a varying amperage. The applied amperage can vary from 1 to 1.1 amps. The PCM/TCM then monitors amperage at the return line.

NOTE: Test numbers refer to numbers on diagnostic chart.

Checks the ability of the PCM/TCM to command the solenoid.
Checks internal transmission harness and solenoid for incorrect resistance.