The ignition control module is a component that regulates the ignition in an engine’s combustion chambers. As the name suggests, the module delivers power directly to the spark plugs at the correct moments so they can ignite the fuel and air mixture in their chamber.
A bad ignition control module causes combustion problems like misfiring and idling. Besides that, a failed module will also cause starting problems or cause the engine to stall midway. It’ll also trigger the Check Engine light to turn on and display fault codes through the onboard diagnostics system. However, the module has nothing to do with the fuel system and won’t stop fuel from flowing.
The following sections will help you understand the symptoms to look out for when your ignition control module goes bad. Besides that, you’ll also learn the module’s relation to the fuel system and why it will not prevent fuel from flowing to the engine.
What Are The Signs Of A Bad Ignition Control Module?
Like all other car components, the ignition control module can go bad if it’s defective or experiences excessive wear. However, there’s some good news and bad news about that problem.
The bad news is that it’ll affect your engine’s ability to function correctly. That means it’ll also make it challenging to drive your car safely, assuming you can start the engine at all.
In other words, a bad ignition control module could immobilize your vehicle until you resolve the problem.
Thankfully, the good news is that you can quickly tell if you have a problem with the ICM. That means you can troubleshoot and resolve the issue quickly, unlike other car problems that sneak up on you because they show no noticeable symptoms.
So, here are the key signs that your ignition control module is bad and requires your attention:
1. Check Engine Light On
The Check Engine light is your first hint of a problem with the ignition control module. The light sits on your dashboard and only illuminates if there is a problem with the engine or one of its components.
In this case, you must understand that the ignition control module is a significant part of the engine’s system. As a result, problems in the module will trigger the Check Engine light.
Unfortunately, the Check Engine light doesn’t give you much of an idea about what’s triggering it. A long list of other problems can also trigger the light to turn on, so you’ll have to troubleshoot further.
Still, the Check Engine light is often the first sign you’ll see when the ignition control module goes bad.
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2. Problems Starting
Another tell-tale sign of a problematic ignition control module is problems starting the vehicle. Typically, an engine will start within 1-2 seconds of you turning the key in the ignition.
However, a delay in that process strongly hints that the ignition control module should be fixed. More specifically, the module isn’t delivering power to the spark plugs to kickstart the engine’s combustion process.
There could be varying degrees to your starting problems. For example, the starting might take several seconds longer than usual. Alternatively, you might also find that the engine starts very rough or doesn’t start at all.
When you experience any of the problems above, it’s best to troubleshoot the ignition control module for problems. Even if it’s not the root cause, ruling it out quickly will save you plenty of time and effort as you troubleshoot the starting problem.
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3. Erratic Engine Behaviors (E.g. Misfiring)
Sometimes, a defective ignition control module won’t be known until the engine runs. When it does, you’ll experience symptoms in the form of erratic engine behaviors.
When the ignition control module goes bad, it’ll prevent your engine chambers from combusting the air and fuel mixtures inside. As a result, you’ll experience one or more of the following:
- Rough idling
- Weak or unresponsive acceleration
- Overall, jerking or shaking in the car
None of the above will happen when the engine and its systems function correctly, igniting the air and fuel mixture inside its chambers. However, a problematic ignition control module will undermine that process and cause the vehicle to show erratic behaviors.
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As you read above, the ignition control module can prevent one or more modules from igniting the fuel and air inside. Unfortunately, that will cause the engine’s combustion process to become unstable and unreliable.
When the problem is much more severe, the module will fail to simultaneously send power to all the spark plugs. That complete failure of the ignition control module will cause your engine to shut off.
In other words, your car stalling in the middle of the road is a tell-tale sign that the ignition control module has failed completely.
As you can imagine, stalling is a very severe symptom of an ignition control module going bad. That’s because it will immobilize your car entirely, preventing the engine from running.
At that point, your only solution is to replace the module on the spot or tow your vehicle to a workshop.
Read: Dealing With a Car Engine Derate
5. Fault Codes
The final symptom to look out for when your ignition control module goes bad is the fault code reported by the onboard diagnostics system.
Most modern cars have onboard diagnostics, consisting of sensors and other electronic devices that monitor the car’s condition. You or your trusted mechanic can plug a code reader or scanner into the onboard diagnostics port in your vehicle (somewhere underneath your steering wheel) to download any fault codes that might be active.
When your ignition control module goes bad, it’ll show fault codes that tell you the problem. Then, you or your mechanic can attend to the problem and resolve it quickly.
Read: Automatic Transmission Warning Light. How To Troubleshoot?
Will A Bad Ignition Control Module Stop Fuel From Flowing To The Engine?
No, a bad ignition control module will not stop fuel from flowing to the engine. That’s because the module only controls the delivery of power to the spark plugs inside the engine.
To put it simply, the ignition control module is only concerned with causing sparks inside the engine’s combustion chambers. It has no control over your car’s fuel system and, therefore, cannot stop the fuel from flowing to the engine.
Instead, the fuel system and its components control fuel flow to the engine. More specifically, the fuel pump, controlled by the crankshaft or camshaft, is the component you should focus on.
The fuel pump draws gas out of the tank and drives it through the fuel lines towards the engine. As long as the fuel pump is functioning correctly, the engine will receive the fuel it needs to operate.
So, if you find that your engine is starved of fuel, the root cause is somewhere in the fuel system instead of at the ignition control module.
A combustion engine needs a few different things to function, namely fuel, air, and sparks from the spark plug. The ignition control module is responsible for the ‘sparks’ part of that equation.
The module ensures that each spark plug has enough electrical power at the correct moments to continue the engine’s combustion process.
So, when it goes bad, the module will cause erratic engine behaviors like rough idling, misfiring, and so on. What those problems have in common is the failure to combust in one or more engine chambers, due to a failure in the ignition control module.