What is the icm on a car?

The ICM or the Ignition Control Module is the brains behind the spark plugs. The ICM tells the spark plugs when to fire and lets the engine know when gas needs to be released for proper engine ignition. Sometimes if your ICM is out or going bad, you may be able to start your motor up nicely once and then when you turn it off it may not start back up but it rarely ever goes out.

mechanic for 10yrs