How to Check & Replace the ICM

The ignition control module (ICM) modulates the electrical signals to a vehicle's distributor and spark plugs, allowing the ignition system to operate properly. If the control module is not working, it can prevent the engine from starting or cause the system to run sporadically. The ICM is typically located near the master brake cylinder on the driver's side of the engine compartment. You can check and replace the ICM in about a half-hour with some basic tools.

Instructions

Checking the Ignition Control Module

1

Set the multimeter testing tool on Volts DC mode and locate the No. 4 module on the ignition control module. Connect the red multimeter test lead probe to the No. 4 circuit wire and connect the black lead wire to the negative battery terminal.

2

Turn the ignition key to the "on" position without starting the engine and watch the reading on the multimeter tester. The tester should read 12 volts DC. If not, the ignition control module should be replaced.

3

Turn off the ignition with the key and remove the testing lead wires from the module and the negative battery terminal.

Replacing the Ignition Control Module

4

Unfasten the negative battery cable from the battery terminal with an open-end wrench and move the cable out of the way. Unfasten the hex screws that are securing the ignition control module to the vehicle frame on the driver's side of the engine compartment with a nut driver.

5

Note how the electrical wires are attached to the ignition control module and remove each wire from the module. Remove the ignition control module from the engine compartment and discard the control module.

6

Attach the electrical wires to the new ignition control module the same way they were attached to the old module. Fasten the new ignition control module to the vehicle frame with the hex screws and connect the negative battery cable to the battery terminal.