Ignition Control Module (ICM)
- Turn ignition off. Disconnect a spark plug wire. Connect Spark Tester (D81P-6666-A) to disconnected spark plug wire. Crank engine and observe spark tester. If spark is a continuous strong Blue spark, ICM circuit is okay. If spark is not a continuous strong Blue spark, go to next step.
- Check ICM Signal From PCM Turn ignition off. Install Breakout Box (007-00033). Connect PCM to breakout box. Disconnect distributor 3-pin connector. Crank engine. Measure voltage between ground and ICM test pin (No. 36) at breakout box. If voltage is more than .7 volt, go to next step. If voltage is .7 volt or less, perform CIRCUIT TEST CID and CKP1 in TESTS W/CODES - EEC 2.5L article in the ENGINE PERFORMANCE section. If results of both circuit tests are okay, replace PCM.
- Check For Open ICM Wire Disconnect 6-pin distributor connector. Measure resistance between ICM test pin (No. 36) at breakout box and ICM terminal (Blue/Orange wire) at distributor 6-pin connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open Blue/Orange wire.
- Check For Short ICM Wire Measure resistance between ground and ICM test pin (No. 36) at breakout box. If resistance is more than 10,000 ohms, go to next step. If resistance is 10,000 ohms or less, repair short to ground in Blue/Orange wire.
- Check Ground At Distributor Measure resistance between ground and GND terminals (Black/White wire and Black/Red wire) at distributor 6-pin connector. If resistance is less than 5 ohms, go to next step. If resistance is 5 ohms or more, repair open GND wire.
- Check Power To Distributor Turn ignition on. Measure voltage at PWR terminal (Black/Pink wire) of distributor 3-pin connector. If voltage is more than 10 volts, replace distributor. If voltage is 10 volts or less, repair PWR wire between distributor and ignition switch.