Ignition Control Module (ICM) Functional Check

INSPECTION

PROCEDURE

1. Check the power supply to the ignition control module. Disconnect the wiring harness from the ICM. With the ignition switched ON (engine not running), check for voltage at the following points:
a) On V6 models, connect a voltmeter between the black/yellow wire terminal (terminal No. 2) and body ground. The meter should indicate battery voltage;

b) On 4-cylinder models, remove the distributor cap and rotor, then disconnect the black/yellow wire from the ICM and check for voltage between its terminal and ground with the ignition ON and the engine not running.

2. Check the ignition circuit and related components. If there is no voltage at the ICM, check the wiring between the module and the ignition switch (refer to the Electrical Systems chapter). Always check the ignition switch fuses No. 41 (100 A) and No. 42 (50 A) in the relay/fuse box under the hood first. Also check fuse No. 6 (15 A) in the junction block under the instrument panel. Carefully inspect the electrical circuit and make sure the ignition switch supplies power to the ICM when the key is turned to the ON position. If necessary, refer to the wiring diagrams.
3. Check the power supply from the ignition coil to the ICM. With the ignition switched ON (do not start the engine), check for voltage between the white/black (4-cylinder VTEC engines), white/blue (4-cylinder non-VTEC engines) or blue (V6 engines) wire and body ground. Battery voltage should be present.
4. If there is no voltage, check the circuit between the applicable wire and the coil. Also check the coil windings (terminals A and B on 4-cylinder engines and terminals 1 and 3 on V6 engines) for internal open circuits (refer to Ignition Coil Inspection and Replacement).
5. If the coil and circuit wiring are good but no spark is produced, replace the ICM.