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Force Motor Circuit Check: 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 the appropriate line pressure for a given load, then regulates the pressure by applying a variable amperage to the force motor. The applied amperage varies from .1-1.1 amps.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. Checks the PCM and TCM's ability to command the force motor.
  2. Checks for voltage at PCM/TCM.
  3. Checks internal transmission harness and force motor for low resistance.
  4. Checks for short to ground.
  5. Checks internal transmission harness and force motor for high resistance.
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