Symptoms of a bad ignition control module?

If you are reading this article, it simply means you want to acquired knowledge about symptoms of a bad ignition control module.

An ignition control module controls the timing of spark plugs in an internal combustion engine.

It is connected to the distributor cap and rotor assembly. However, you should know some bad ignition control module symptoms.

 Note:  more information will be covered in this post.

When the engine starts, the ignition control module (ICM) sends a signal to the distributor to open the points at the correct time.

 The ICM is under the vehicle’s hood and attached to the distributor using a set screw.

The ignition control module is designed to work with specific engines and their components.

An ICM may have several functions, including fuel injection, ignition timing, and knock detection.

A properly functioning ignition system is critical to the performance of any vehicle. If the ignition system fails, the engine will not start, or if it starts, it may run poorly.

The ignition system may fail due to mechanical, electrical, or poor maintenance.

How to test the ignition control module.

To properly check the ignition control module, you must know how to measure the voltage across the ignitor coil. You can do this using a multimeter.

Remove the cover plate and the ignition control module (ICM) from the engine compartment. Then turn off the ignition switch.

Connect the red lead of the multimeter to the battery’s positive terminal.

Connect the multimeter’s black lead directly to the battery’s negative terminal.

Turn the dial on the multimeter until you reach the correct range for measuring voltage.

Check the reading on the multimeter.

Measure the voltage between the battery’s positive terminal and the ground connection on the ignition switch.

If the voltage reading is less than 12 volts, then replace the ignition switch.

Measure the voltage between the positive battery terminal and the ground connection on each coil. If the voltage reading on any coil is less than 12 volts (or if the voltage reading is greater than 15 volts), then replace the ignition switch and/or coils.

Check the wiring connections at the coil terminals. If any wires have been disconnected, reconnect them.

Reinstall the ignition switch and recheck the voltage.

If the voltage reading exceeds 12 volts, replace the ignition switch and the coils.

Lastly, turn the distributor center shaft by hand. As the distributor is turning over, carefully examine the distributor rotor.

The distributor or distributor gears are broken if the distributor’s rotor cannot turn.

What are the symptoms of a bad ignition control module?

Bad Ignition Control Module

Bad smell.

If your car has an awful smell after being driven for a short distance, chances are it’s time to get your ignition control module replaced.

The smell could mean the air intake valve is clogged or the ignition control module is damaged. Have your car inspected once you notice any strange odors from the engine compartment.

Engine overheating.

This is among the obvious signs of a bad ignition control module. When your car overheats, the engine is working harder than expected.

This may cause damage to the engine. If you notice excessive engine temperature, take your vehicle to a mechanic immediately.

No power.

If your car doesn’t start, you need to check the battery first. If the battery is dead, replace it right away.

If the battery is still good, try charging it again. If that doesn’t work, then it could be a sign of a bad ignition control module.

You’ll need to contact a professional to fix this issue.

Poor performance.

If your car seems sluggish, it could be due to several problems. One of them is a bad ignition control module.

First, make sure that the gas tank is filled.

Next, check the oil level and change it if necessary. Finally, check the coolant levels.


If your car shakes uncontrollably, it could be a loose steering wheel, a loose suspension system, or a defective ignition control module.


Stalling happens when the engine stops running altogether. When this happens, the car won’t move unless you push the brake pedal.

If you notice stalling, pull over immediately and turn off the engine. Then, please wait until the engine turns back on before restarting it.

Can you bypass an ignition control module?

Yes, you can!

You may have heard about people who have been able to bypass their ignition control modules (ICM) on vehicles.

There are many different ways to do this, but they all work similarly. You must remove the ICM’s power supply wire and connect it to the battery-positive terminal.

Once that’s done, you should be able to start the vehicle without any problems.

Alternatively, you can jumpstart your car by using a jumper cable. A jumper cable is a short length of wire that plugs directly into the positive terminal of a battery and the negative terminal of another battery.

You can use a jumper cable to jumpstart a car if both batteries are charged. However, it would be best if you did not attempt to jumpstart a dead battery using a live battery.

You could get shocked if you accidentally touch the terminals of a live battery while connecting the cables.

How often do ignition control modules fail?

The ignition control modules fail when you ignore the warning signs from other units.

When the ignition control module fails, the power goes directly to the igniter coil, causing the igniter coil to overheat and burn out.

If the ICM works correctly, the igniter coil may burn out prematurely, resulting in poor combustion.

Once the igniter coil burns out, the entire system shuts down. A burned-out igniter coil causes the whole system to shut off.

If the ignitor coil is damaged, it could cause the system to malfunction.

The ignition control module is essential to the vehicle’s electronic system.

How Last Does Ignition Control Module Last?

It should last for more than 5–10 years or 100,000 miles if properly maintained. Note that the ignition control module can be affected by many factors, including age, temperature, usage, etc.

Signs of the ignition control module going bad.

Loss of power.

Loss of power could mean so many things in a car. A common problem is a bad ignition control module. If the ICM fails, then the vehicle will not start. A faulty ICM may cause the engine to fail to turn on at all.

Lights flickering.

Flickering lights mean the ignition control module (ICM) is not working correctly.

If the lights flicker, you should immediately shut down the car and contact your auto mechanic.

Smoke is coming out of the tailpipe.

Smoke coming out of the tailpipe means that the ICM is overheating. If white smoke comes from your exhaust or your tailpipe is too much, you should have your car inspected as soon as possible.

Bad smells ooze out.

Bad smells mean that the ICM is burning out. If you smell burnt plastic or rubber, you should immediately stop using the car and contact a certified electrician.


Overheating means that the ICM is not adequate. You should immediately call an auto technician if you feel warm air blowing out of vents and hear a humming sound

What happens when the ignition control module goes bad?

Bad smell.

If you notice a strong odor coming from your car’s engine compartment, the probabilities are that it could mean something is wrong.

When the ignition control module (ICM) fails, it causes the vehicle’s computer system to malfunction, resulting in a loss of power and fuel injection.

As a result, the engine runs rough and produces a foul-smelling exhaust.

Engine stalls.

If the ICM fails while driving, the engine may stall out. In some cases, the failure may cause the engine to shut off completely.

Poor performance.

When the ICM malfunctions, the engine may not perform at its best. You may experience poor acceleration, sluggishness, or jerky starts.

Noisy operation.

A faulty ICM may make loud noises when the engine is running. These sounds may range from a high-pitched whine to a deep rumble.

Check the engine light.

If the check engine light comes on, the ECU has detected a problem. A malfunctioning ICM may cause the light to illuminate.

Reduced gas mileage.

As mentioned earlier, if the ICM fails, the engine may run poorly and produce less horsepower than usual. This results in lower gas mileage.

Increased emissions.

If the ICM malfunctions and the engine does not start properly, the vehicle may emit higher carbon monoxide and hydrocarbons.

How do you know if your control module is bad?

Your engine starts making strange noises.

The ignition control module controls the ignition system and fuel injection system.

When these systems malfunction, they can cause strange sounds from the engine. These sounds may include grinding, clicking, or popping.

Your car won’t start.

If your car refuses to turn over, then it could mean a problem with the ignition control module.

Your car stalls out.

When your car stalls out, the electronic control unit (ECU) isn’t receiving any information from the sensors.

It causes the ECU to think something is wrong with the car and shuts down the engine.

Your car doesn’t accelerate.

If your car fails to accelerate, then it could mean the ignition control module is having problems. It will need Urgent attention.

Your car runs rough.

Another conspicuous sign to look out for if your ignition control module is wrong is if your car runs rough. It could mean that the engine control module (ECM) is having issues.

Your car overheats.

A known ignition control module problem is engine overheating. So, once your car overheats, it could mean that your ECM is having trouble, or any other vital component might be damaged.


If the ignition control module is not working correctly, the engine will run rough, perform poorly, and even stall out. If you have been experiencing any of these symptoms, it is time to replace your ICM.

To avoid this problem, keep the engine oil clean, and change the oil regularly. Also, make sure the air filter is clean.

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