ICM Test
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Joined: Oct 2003
Posts: 447
From: Portsmouth, Ohio
ICM Test
Can someone direct me in the right direction on how to check the ICM, when it's off the car. I have the ohm metere just don't know what the measurements are suppose to be.. Any website or service bulletin with help. Thanks Guys.
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Joined: May 2003
Posts: 2,275
I'm not formiliar with on bench testing of the ICM but if you don't find the answer you're looking for maybe this will help.
The signal from the PCM to the ICM is on the white wire of the ICM and goes to pin B and at the PCM is on the black connector pin 5. The first thing to do is disconnect both connectors and check continuity from pin B of ICM to pin 5 of the PCM connector. You may need a second wire to reach it with meter. Obviously if there is no continuity, you have a wire to fix.
If ok, connect both ends and put the meter on AC Volts. While cranking the engine, look at the signal on the white wire of the PCM. It should have between 1 and 4 volts AC on it. Remember to ground the black lead.
If no AC signal, pull the connector at the PCM (black connector) and check the signal coming out of pin 5. If there is no signal coming out of pin 5 then most likely (notice I said most likely), the PCM is bad.
If the AC signal is getting to the PCM on the white wire, you must now look at the signals from the ICM to the coil. Ignition off. Meter set to DC Volts. First check for a good ground to the ICM. Put a meter lead on the + battery terminal and probe the black wire pin C on the ICM with the other lead. It should show a full battery voltage (12 or more volts).
If not you have a bad ground.
Ignition on. Meter set to DC Volts. Now check the pink/black wire on pin A of the ICM and the white/ black wire on pin D of the ICM for battery voltage (12 or more volts) remember to ground the other lead.
If the voltage is there, the problem is the coil. If it is not on those 2 pins, you have to determine if the wire from the coil to the ICM is broken, or if the connectors are bad or the coil is bad.
Also if the voltage is not on those 2 pins, check the #11 fuse (10 amp) the supplies the ignition. If blown, no voltage either.
If the AC signal is getting to the ICM and the ICM has 12 volts on pins A and D, the ground is good to the ICM, and you still have no spark the ICM is probably bad.
The signal from the PCM to the ICM is on the white wire of the ICM and goes to pin B and at the PCM is on the black connector pin 5. The first thing to do is disconnect both connectors and check continuity from pin B of ICM to pin 5 of the PCM connector. You may need a second wire to reach it with meter. Obviously if there is no continuity, you have a wire to fix.
If ok, connect both ends and put the meter on AC Volts. While cranking the engine, look at the signal on the white wire of the PCM. It should have between 1 and 4 volts AC on it. Remember to ground the black lead.
If no AC signal, pull the connector at the PCM (black connector) and check the signal coming out of pin 5. If there is no signal coming out of pin 5 then most likely (notice I said most likely), the PCM is bad.
If the AC signal is getting to the PCM on the white wire, you must now look at the signals from the ICM to the coil. Ignition off. Meter set to DC Volts. First check for a good ground to the ICM. Put a meter lead on the + battery terminal and probe the black wire pin C on the ICM with the other lead. It should show a full battery voltage (12 or more volts).
If not you have a bad ground.
Ignition on. Meter set to DC Volts. Now check the pink/black wire on pin A of the ICM and the white/ black wire on pin D of the ICM for battery voltage (12 or more volts) remember to ground the other lead.
If the voltage is there, the problem is the coil. If it is not on those 2 pins, you have to determine if the wire from the coil to the ICM is broken, or if the connectors are bad or the coil is bad.
Also if the voltage is not on those 2 pins, check the #11 fuse (10 amp) the supplies the ignition. If blown, no voltage either.
If the AC signal is getting to the ICM and the ICM has 12 volts on pins A and D, the ground is good to the ICM, and you still have no spark the ICM is probably bad.
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