Modern vehicles are equipped with a variety of electronic sensors and modules to control the various engine functions necessary for the vehicle to run. One of these components is the electronic spark control module, commonly referred to as the ESC module, or the ignition module. The ignition module works together with the computer to time the engine’s ignition system for the best performance and efficiency. One of the specific functions of the ESC module is to advance or retard the timing of the ignition system, depending on the operation conditions.

Under heavy load, the module will advance the timing to increase power and will retard it at low throttle and cruising speeds in order to maximize efficiency. The ESC module makes these changes automatically and smoothly, almost to the point where they are virtually unnoticeable to the driver. As the ESC module plays an important role in the operation of the engine, any problems with it can cause issues with the drivability and performance of the vehicle. Usually a bad or failing ESC module will produce a few symptoms that can alert the driver of a potential issue that should be serviced.

1. Engine performance issues

One of the first symptoms of a problem with the ignition module are engine performance issues. If the ignition module fails or has any problems it can lead to performance issues with the vehicle, such as misfires, hesitation, loss of power, and even reduced fuel economy.

2. Engine stalling

Another symptom of a problematic ESC module is the engine stalling. A faulty module may cause the engine to suddenly stall and be unable to start again. Sometimes the engine can still be restarted after a short period of time, usually after the module has been allowed to cool off.

3. Car not starting or engine not sparking

Another common symptom of a faulty ESC module is a no start, or no spark condition. The ESC module is one of the components that directly controls engine spark, so if it fails, it can leave the vehicle without spark. A vehicle without spark may still crank, but will not be able to start or run.

The ESC module is one of the most important components found on many modern ignition systems, and without it most vehicles will not run properly. If you suspect that your ESC module may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if your vehicle needs an electronic spark control replacement.

This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Electronic Spark Control and was authored by Ed Ruelas.


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