What Are the Symptoms of a Defective Ignition Module?

The most common symptoms of a defective ignition module are overheating, unexpected stalling or inability to start the vehicle. Replacing the module is an expensive process, and checking the circuits, electrical connections and temperature issues within the first or second occurrence of stalling can save time and money.

In order to troubleshoot the cause of a failing module:

  1. Check for overheating
  2. If the vehicle starts, stalls and restarts after cooling off, the ignition module is overheating. Temperature issues can be checked by idling the engine for 30 minutes in a well-ventilated area. Tap the ignition module with a screwdriver. If the engine stalls, an overheating module is the most likely source of the issue. It can be cooled with ice water, refrigerant liquid or engine coolant until it can be professionally repaired.

  3. Check for faulty ignition system components
  4. Before replacing the ignition module, rule out other issues within the ignition system. Check loose connections at the cap, rotor and spark plugs, clean the terminal and replace any damaged or broken wires. Check the ignition coil for a spark. Check the output of the ignition module by connecting a light timing tester to the positive terminal of the battery. Determine the flow of the output wire while cranking the starter. If the light blinks, it is working. If it is a blank or a steady light, the module is bad.