Code 73, Force Motor Current (Current Error): Notes

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

The force motor 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 1-1.1 amps.

The PCM/TCM then monitors amperage at the return line. If the return amperage varies more than .16 amp from the commanded amperage for the duration of at least one second, Code 73 will set. Once Code 73 is set, the force motor is disabled and full line pressure will be applied until the next time the ignition switch is cycled. Code 73 will remain stored, but the force motor will resume normal function until the conditions for Code 73 re-occur.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Checks the PCM and TCM's ability to command the force motor.
Checks for voltage at PCM/TCM.
Checks internal transmission harness and force motor for low resistance.
Checks for short to ground.
Checks internal transmission harness and force motor for high resistance.