DTC 23

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

- Wiring Diagram for Code 23 M/C Solenoid Circuit Low.:

CODE 23

M/C SOLENOID VOLTAGE LOW TO ECM

CIRCUIT DESCRIPTION
Code 23 says the ECM has seen the voltage at ECM Term. "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.

CHART DESCRIPTION
Step numbers refer to step numbers on diagnostic chart.
1. Checks for a complete circuit from the battery through the M/C solenoid dwell lead. It should be battery voltage. Battery voltage indicates there may be an open CKT. 411 between the dwell connector and ground. A 0 voltage reading could be caused either by an open between the dwell connector and ign. source or a ground on the ECM side of the M/C solenoid.
2. Checks for B+ on CKT. 439 to the ignition source. The test light should light between the ignition source and ground.
2a. Checks for an open CK 411 the solenoid to ECM circuit. A normal circuit would read about battery voltage at the ECM Term. "18".
3. This step determines whether the fault is in the M/C solenoid, a grounded CKT. 411 to the ECM, or the ECM. A light would indicate a grounded CKT. 411 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 grounded CKT. 411 to ECM Term. "18". If it is grounded, the light will stay "ON".