For optimal engine performance, new vehicles must rely on sensors that constantly communicate the data gathered to the engine control unit. As a result, this control unit will be able to make adjustments and ensure a better driving experience.
The ignition coils form a coil pack that transforms power from the battery into usable electrical energy. It generates a spark that helps each cylinder fire individually and allows your engine to function properly. These parts can also create a cleaner combustion process since no moving parts are involved.
How can you tell if they’ve gone bad?

You can test the coil pack with a special tool called a multimeter. It measures Ohm’s resistance, and you can find the proper resistance for the coil’s windings. With that information, you are able to proceed and find potential problems.
The ignition coils have two separate coils named primary winding and secondary winding. With such a performant tool, you must connect the multimeter’s positive and negative leads to the terminal. Remember that they vary from model to model, so you should check the owner’s manual for more information.
The reading on the multimeter will give you a result to compare with the specifications mentioned by the car manufacturer. If this reading is not within the optimal resistance range, you will need to replace it. We also found the best multimeter for you, so you won’t have to search the market for hours.
AstroAI Multimeter 2000 Counts Digital Multimeter
This versatile and highly accurate digital multimeter can measure the voltage and resistance of various parts. This useful tool is intended for both commercial and personal use, and you can also use it on your household electrical systems.
With a fast sampling speed of 2 times per second, this multimeter is superior compared to other models. The LCD display will display the results. They are visible even in dark environments or during conditions with low visibility.
The double ceramic fuse protects this tool from overloading, while a silicon cover will reduce damage if you drop this tool to the ground. Batteries power this device, and the display will inform you when the battery power is low.
| Name | AstroAI Multimeter 2000 |
| AC/DC Current | Only DC Current |
| Capacitance/Frequency | X |
| Item Dimensions LxWxH | 5.1 x 2.8 x 1.4 inches |
| Item Weight | 0.4 Pounds |
| Power Source | Battery Powered |
Pros
- It’s a great multimeter for basic purposes.
- You can’t beat the price.
- It’s easy to use.
- More than 34,000 people have reviewed the multimeter.
Cons
- It feels a bit cheap.
- You can definitely get higher-end ones.
- It’s hard to find a lot of information about the company.
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How to test them without a multimeter?
While a multimeter will give you accurate results, many more methods will help you test the coil pack. One of them implies unscrewing the coils and leaving them inside the cylinder. As you start the car, the engine will be running, and you can slowly remove one of the coils.
Once you remove it, place a test light in the hole that is holding this part. If it is not working, a constant spark will be produced that can be clearly visible. If the coil is bad or failing, this spark will be missing. You will have to replace the part. Be advised that this method is dangerous and you should wear protective equipment.
Replacement cost
Whether you own a small-sized city car or a large vehicle like the Dodge Ram 1500, replacing the coil packs will take some money out of your wallet. You will only have to replace the coil pack if it goes bad. The retailers that sell them often offer better deals for buying them in packs.
Usually, you should expect to pay between $20 to $40 for a single ignition coil. Unless you replace this part yourself, you also have to consider the labor costs and the extra fees demanded by the auto repair shop.
Here’s the cost of other basic maintenance work.
| Maintenance | Frequency | Expected cost ($) |
| Basic inspection | Every 5,000 miles | 200 |
| Tire rotation | Every 8,000 miles | 70 |
| Wiper replacement | Every six months | $20 |
| Brake pad replacement | Every 20,000 miles | $200 |
How long do they usually last?

After you replace the coil packs with a brand new one, you should expect them to last up to 5 years. Depending on how frequently you drive your car, a coil pack replacement has to be done earlier than 5 years if you reach 120,000 miles.
Even though coil packs are designed to last a long time, constant exposure to heat and friction can accelerate the wearing process. It is recommended that you check their condition from time to time.
Spark plug vs. coil pack
These parts are both essential for your vehicle but are not the same. The ignition coil is located in the ignition system, and it helps create a spark that the spark plugs use to start the engine.
The spark plug is responsible for supplying the spark that ignites the fuel mixture in the engine and starting the combustion process. This part helps with creating the necessary power to move your car. Spark plugs use up to 50,000 volts created by the ignition coil, so it is a complex part.
Have you noticed any of the following symptoms?
- Excessive spark plug gap
- Worn cables
- Excessive vibrations
- Excessive heat
- Rough starts
