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Home >> Geo >> 1990 >> Tracker Base, Automatic >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Code Charts >> Code 41, Ignition Signal Circuit No Signal >> Notes
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Code 41, Ignition Signal Circuit No Signal: Notes

ECM tach signal is 12 volts that varies as ignition coil is toggled to ground. The ECM uses this signal to pulse fuel injector. This code sets if there is no signal or is constant voltage on the line.

NOTE: Test numbers refer to test numbers on diagnostic chart.
  1. This checks for battery voltage on signal line.
  2. This checks noise suppressor for open.
  3. This checks for toggling voltage signal.