Code 54 - M/C Solenoid Circuit High

Code 54 will be set if there is constant high voltage at ECM terminal "18". A short circuit to 12 volts will cause M/C solenoid to remain in the full rich position.

NOTE: The following step numbers refer to the numbers in the accompanying flow chart(s).

This test checks the M/C solenoid resistance to determine if the fault is in the solenoid or ECM harness/ECM. Normal reading for a solenoid is 18-32 ohms.
NOTE: After replacing a faulty M/C solenoid, a system performance test is necessary to be certain the M/C solenoid was the only faulty part. Solenoid may have caused the ECM to fail, this will reset code.
This test checks if reason for high voltage to term. "18" is a faulty ECM or a short to 12 volts on that wire. If the test light to ground lights at the M/C solenoid test lead with both ends of harness disconnected, there is a short to 12 volts in the wire.

Fig 1: Code 54, M/C Solenoid Circuit High

Fig 2: Code 54, M/C Solenoid Circuit High