Circuit Description

The MIL is illuminated by PCM if diagnostics have detected certain errors related to engine performance or engine sensor status. When PCM is commanding MIL on, voltage potential of circuit will be low (near zero volts). When PCM is commanding MIL off, voltage potential of circuit will be high (near battery voltage). Primary function of PCM is to supply ground to MIL control circuit.

DTC will set when the following conditions are present:

• MIL is requested on.
• Voltage to MIL control circuit is high (near battery voltage).

Or

• MIL is requested off.
• Voltage to MIL control circuit is low (near zero volts).