About Monitored Circuits

NOTE:
The PCM can detect certain faults in its systems, the following is a list of the types of faults the PCM can detect.

MONITORED CIRCUITS

Open or Shorted Circuit - The PCM can determine if the input signal from the sensor is within its range and if the sensor circuit is open or shorted.

Output Device Current Flow - The PCM can see if the output devices are hooked up. If a problem exists with an output devices' circuit, the PCM can determine if it is open, shorted high, or shorted to ground.

Oxygen Sensor - Once the system has entered closed loop, the PCM checks that the oxygen sensor is switching between rich and lean. Refer to Powertrain Management/Computers and Control Systems/Powertrain Control Module/Description and Operation.