DTC 23

Code 23 - M/C Solenoid Voltage Low To ECM:

Wiring Diagram for Code 23 - M/C Solenoid Voltage Low To ECM:

CODE 23 - M/C SOLENOID VOLTAGE LOW TO ECM


Circuit Description:

Code 23 says the ECM has seen the voltage at ECM 18" stay low instead of rising and falling as the M/C solenoid is turned "ON" and "OFF". This could be caused by an open in the M/C solenoid circuit or a ground on the ECM side of the M/C solenoid.

An open would cause a full rich condition and cause poor economy, odor, smoky exhaust or poor driveability. A ground would cause a full lean condition and cause poor driveability.


Test Description:

1. Checks for a complete circuit from the battery to the M/C solenoid dwell lead. It should be battery voltage. Battery voltage means there might be an open circuit between the dwell connector and ground. No voltage could be either an open between the connector and battery or a ground on the ECM side of the M/C solenoid.

2. Checks for B+ on the pink ignition source wire. Test light should light between the ignition source and ground.

2A. Checks for an open in the solenoid to ECM circuit. A normal circuit would read about battery voltage at the ECM Terminal "18".


3. This step determines whether the fault is in the M/C solenoid, a ground in the circuit to the ECM, or the ECM. A light would indicate a ground in circuit to Terminal "18" or a faulty ECM. A voltmeter can't be used because it is normal to have enough current flow through the ECM even with the circuit open to make a voltmeter read, but not enough to light a test light.

4. This checks for ground in the wire to ECM Term. "18". If it is grounded, the light will stay "ON".