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Code 39 - Clutch Switch Error: Notes

Clutch switch is normally closed when the clutch pedal is at rest. When clutch is depressed, switch will change from off status to on status. ECM runs a diagnostic test that looks for a change of state in the switch logic. If there is a failure in the clutch switch circuit, a Code 39 will set and the SERVICE ENGINE SOON light will illuminate. Code 39 will set when engine temperature is greater than 194°F (90°C), vehicle speed is greater than 40 MPH and clutch switch test fails 4 consecutive times in one ignition cycle.

NOTE: Test numbers refer to numbers on diagnostic chart.
  1. When clutch is depressed, switch should go from closed to open and status on a scan tester display should change from off to on.
  2. This test will check for a poor ground to clutch switch.
  3. This test will determine if clutch switch is being supplied with battery voltage or if circuit is shorted to ground.