Powertrain Controls - ECM/PCM

DTC 73 Pressure Control Solenoid (Current Error):

Pressure Control Solenoid Circuit:

Circuit Description:
The pressure control solenoid is a PCM controlled device used to regulate transmission line pressure. The PCM compares TP 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. The applied amperage can vary from 0.1 to 1.1 amp. The PCM then monitors the amperage at the return line. If the return amperage varies greater than 0.16 amp from the commanded amperage for at least one second, DTC 73 will set. When DTC 73 sets, the full line pressure will be applied causing harsh shifts until the next ignition cycle. DTC 73 will remain stored in memory and the pressure control solenoid will resume normal operation until the conditions for DTC 73 re-occur.

Test Description:
Number(s) below refer to circled number(s) on the diagnostic chart.

1. This test checks the ability of the PCM to command the pressure control solenoid.
2. This test checks for voltage at PCM.
3. This test checks internal transmission harness and the pressure control solenoid for low resistance.
4. This test checks internal transmission harness and the pressure control solenoid for high resistance.

Diagnostic Aids:
Check for poor connections at PCM and at transmission pass-thru connector.