An ignition module is also known as a control unit or an ignitor. In many internal combustion engines, an ignition control module (ICM) is often found inside or near the car distributor, which is an enclosed rotating shaft utilized in spark-ignition internal combustion engines with mechanically timed ignition. What does the ignition control module do? ICM generates and controls the amount of energy required for a spark plug to ignite. It opens or closes a ground circuit to the primary winding of the ignition coil. When this happens, the coil is able to generate enough voltage to ignite a spark plug.
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The ignition control module normally takes an input from a sensor inside the distributor (typically the crankshaft position sensor or camshaft position sensor) in order to ground the coil at the proper time. If the spark plugs misfire or quit producing a spark, the vehicle's performance suffers. The engine will not run properly unless each spark plug is ignited at the exact same time. That’s how important an ignition control module is and we will learn more about it in this article.
History of How Ignition Control Module Came About?
Since the late 1940s, GM has experimented with electronic ignition systems (which use a transistor in a module instead of contact points). However, ignition systems began to evolve in a big way. In 1972, Chrysler made electronic ignition standard on all of their vehicles, with a module actuating the oil-filled coil using data from a wire-wound stator magnet located adjacent to a spinning reluctor within the distributor. For on-the-fly timing modifications, the distributor still had a vacuum advance and an internal centrifugal advance.
Oil-filled coils began to disappear in the mid-70s, and were replaced by potted E-core ignition coils that worked in the same way as the oil-filled coils, only the voltage jumped from roughly 50,000 volts to about 100,000 volts. By this time, transistor-based ignition modules were the norm, and as computers became more common in automobiles, the ECM began to alter the ignition module's timing of the igniting event.
Distributors began to become obsolete in the mid-1980s, and coil packs took their place. However, ignition modules remained the box that fired the coils, albeit with ECM altering the module's ignition pulse timing. The ignition module became a part of the ECM/PCM as it began to receive the Crankshaft position sensor (CKP) signal and operate the coil primary triggers.
What is the purpose of a vehicle's ignition system?
So we could better get the picture of what does the ignition control module do, let us first discuss the basics of what a vehicle’s ignition system role is. Ignition System is a system that regulates a vehicle's ignition. The ignition system consists of components and cables that work together to generate and transport the voltage needed by your spark plugs. This process generates a spark, which raises the temperature of the air-fuel mixture and initiates combustion.
The ignition coil provides power to your vehicle's ignition system. It usually comprises two copper wire windings that are independent of one another. The ignition switch is attached to the positive terminal of a single-coil ignition system, which receives current from the positive battery terminal. In order to fire the spark plugs through the distributor, the negative terminal is linked to the ICM, which opens and closes the primary ignition circuit.
How The Ignition Control Module Works?
To better understand the answer to the question, “What does the ignition control module do,” you must also understand how the ignition control module works. In most cases, the ignition control module is mounted on the engine. Because some components in ignition control modules are heat-sensitive, the interior circuitry is frequently encased in insulating material. Between the engine and the ignition control module, a heat shield might be used.
The magnetic pulse generator in the distributor provides input to the ignition control module, which turns transistors on and off. The magnetic pulse generator sends out an AC voltage signal that is proportional to the engine speed and crankshaft position. The ignition control module translates the analog signal into a digital signal, which the ignition control module uses as an on/off switch.
The primary winding of the ignition coil is grounded by contact points inside the distributor in mechanically timed engines. The points open at predictable intervals when the distributor shaft spins, breaking the circuit. The primary's magnetic field collapses as a result, allowing the secondary wiring to generate a high voltage.
What does the ignition control module do? Electronic ignitions replace the functionality of the points with an ignition control module and an optical or magnetic sensor inside the distributor. The internal sensor in an engine with electronic ignition delivers an input to the ignition control module as the distributor shaft rotates.
The module can then cut the ground circuit to the ignition coil primary, allowing the device to function similarly to mechanically timed ignitions. Electronic ignitions may also allow the onboard computer to change the timing in order to improve fuel efficiency or reduce exhaust emissions.
As mentioned, ignition control modules are typically made up of one or more heat-sensitive transistors or other electrical components. Some modules are housed inside or near the distributor, where they are frequently exposed to extreme temperatures. Although many control module designs include some form of insulating material to prevent heat damage, failures are very prevalent. When an ignition control module fails, the coil primary ground circuit is not properly terminated, and the engine will not start.
Depending on the vehicle you own, the complexity of your ignition system may differ. The powertrain control module on most modern vehicles receives sensor input and controls the operation of your ICM. On some vehicles, the ignition timing is only controlled by the ICM at lower RPMs. To comprehend what the ignition control module accomplishes, you must first comprehend how the ignition system operates.
What are the symptoms of a bad ignition control module?
Though defective ignition control modules usually stop working completely, causing the engine to die and not restart, failures are frequently caused by heat. An ignition control module's failure pattern is for the engine to die once it gets hot, then start and run perfectly after it cools down. When the module is cold, it may test fine, making these types of failures difficult to diagnose. But just to give some idea here are some symptoms of bad ignition control module:
- Problems with Acceleration
When the gas pedal is pressed, the car may shake, tremble, or jerk. During speed increases, there may be hesitancy or a lack of power.
- Problems with Temperature
Overheating is a typical sign that you may have a problem with your ignition module. Overheating ignition modules will eventually stop working completely, resulting in electrical shorts, engine stuttering, lower gas mileage, power loss, stalling, and gasoline aromas in the exhaust.
While the automobile is still running, you can check for overheating. Allow 30 minutes for the engine to idle before tapping the module with a screwdriver. The car may stall, which strongly suggests that the overheating you're experiencing is caused by the ignition control module.
If you find yourself in an emergency situation with an overheated module, you can cool it down with ice water, engine coolant, or refrigerant fluid. However, this is simply a temporary fix that should be used as a last resort until you can go to a repair facility.
- There is no power
It's possible that the engine will turn over but not start. It may take several attempts to start the vehicle, and once it does, it will lose power. If your car stalls during operation and refuses to restart, it is most likely due to loose or corroded electrical connections in the ignition module. In this situation, inspect the switch, clean oxidized terminals, and, if required, replace broken wires.
If the problem is not handled after the first or second recurrence, the circuits may be severely damaged by overheating. If the automobile won't start, you'll need to use a light timing tester to verify the output of the ignition control module.
While cranking the starter, connect the timer to the positive terminal of the battery and check the continuity of the black output wire. The module is good if the light blinks. The module is defective if the light is blank or continuous. You must rule out other ignition system components before attempting to replace the control module. The module is costly, and replacing it is a time-consuming process.
Look for a spark in the ignition coil. Check the wires around the cap, rotor, and spark plugs. If the automobile starts but has timing issues, adjust the spark plug timing according to the manufacturer's guidelines using a tester light and wrench.
- Check Engine Light Turned On
When your ignition system senses a problem, your check engine light will illuminate. If you have an OBD scan tool, you can use it to extract the error code from your vehicle's OBD port. Ignition-related error codes range from P0300 to P0399 on the diagnostic code scale. You can always take your vehicle to an auto repair shop for inspection if you don't have the right diagnostic tools.
Can you drive with a bad ignition module?
Now that you know, “What does the ignition control module do?” you will understand the risks of having bad ignition module. A malfunctioning ignition control module can be a tremendous pain. While you may still be able to drive one second, it can still cause a variety of engine performance issues, such as preventing the engine from starting or stalling as you speed down the road, only to allow you to resume driving as if nothing had happened a few minutes later. There are a few things you should know about dealing with a possible broken ignition module on your car before any of these symptoms send you troubleshooting components or systems unrelated to the main cause of the problem.
What makes an ignition control module go bad?
The failure of an ignition control module is frequently linked to age and excessive heat as well. The original distributor is installed in the majority of the cars that have this problem on a regular basis. The bushing in the shaft of the distributor deteriorates as it ages and wears, causing excessive heat.
How much does it cost to replace the ignition module?
The cost of a replacement ignition control module can range from $50 to $250. Labor rates might range from $70 to $90 per hour. Keep in mind that these are merely estimates, and you'll need to figure in costs for other repairs as well.
While we recommend that you shop for the best and most likely cheapest offer for replacing your ignition control module, we also recommend that you be cautious of the repair shop and make sure you're dealing with knowledgeable specialists. What does the ignition control module do for your car is very important and having it installed properly will ensure that you will not risk causing significant engine problems that will cost you thousands of dollars in the long run?
If you wish to repair your vehicle's ignition control module yourself, make sure you have the necessary mechanical skills. This will allow you to do the job correctly without causing any other issues. Keep in mind that most DIY projects fail the first time, according to most experts, so there's a good risk you won't replace the part correctly.
How do you test a bad ignition control module?
Before you replace your ignition module, test your ignition control module first and avoid wasting money and energy replacing it without really needing to. That is because engine misfires can also be caused by malfunctioning ignition-related components. Before testing the ICM, spark plugs, spark plug wires, and ignition coils are some of the items that are routinely replaced to repair misfires.
Many resources are available for you online to guide you when conducting the test for your ignition control module. If you want to diagnose the problem yourself, you can utilize them. To get started, you'll need a spark tester, a test light, and an ignition control module tester. However, because testing the ICM is a complicated procedure, it's best to leave it to the pros, especially if you're not a seasoned DIYer.