Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Ignition Control Module Circuit Test
Check ignitor after checking ignition coil. If tach is operating, Ignition Control Module (ICM) is okay.
- Remove distributor cap, rotor, and cover. Disconnect wires from ICM.
- Turn ignition on. Check for voltage between ground and Black/Yellow wire. If battery voltage exists, go to next step. If battery voltage does not exist, repair Black/Yellow wire between ignition switch and ICM.
- Check for voltage between ground and Green wire (F22B2 engine) or White/Black wire (F22B1 engine). If battery voltage exists, go to next step. If battery voltage does not exist, repair Green wire (F22B2 engine) or White/Black wire (F22B1 engine) between ignition coil and ICM.
- Turn ignition off. Disconnect ECM/PCM 32-pin connector. Check continuity of Yellow/Green wire between ECM/PCM connector terminal A20 and ICM. Continuity should exist. Check for continuity between ground and Yellow/Green wire at ECM/PCM connector terminal A20. Continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, repair open or short to ground on Yellow/Green wire.
- Reconnect ECM/PCM 32-pin connector. Disconnect instrument cluster 22-pin connector C609. Check continuity of Blue wire between instrument cluster connector C609 terminal No. 2 and ICM. Continuity should exist. Check for continuity between ground and Blue wire at instrument cluster connector terminal No. 2. Continuity should not exist. If continuity is as specified, go to next step. If continuity is not as specified, repair open or short to ground on Blue wire.
- If no problem is found, reconnect instrument cluster 22-pin connector C609 and replace ICM.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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