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How To Check An Ignition Coil

If you have a car with a metal spark plug wire, you may have to check it sooner rather than later. Check engine codes (P0171, P0172, and P0173) indicate that the ignition coil is bad and need to be replaced. However, before you go out and replace the entire ignition coil, it’s important to first confirm that this is what’s causing the check engine code. To do this, you can use a scan tool like OBD-IIdi or CarMD to analyze your car’s data stream and see if there is an issue with the ignition coil. If you do decide to replace the ignition coil, be sure to take care of any other issues that may be causing the code as well. For example, if your car has a broken suspension, replace that as well. Check out our blog post for more information on how to identify and fix common car problems.

What is an ignition coil?

An ignition coil is a small, cylindrical device used to ignite the air/fuel mixture in an engine. When the coil is energized, it creates a spark that ignites the fuel. Many Jaguar and Land Rover models use platinum-coated coils because they are known to create a more reliable spark.

How to check an ignition coil

There are a few ways to test an ignition coil. One is to use an ohm meter to check for continuity between the coil and the spark plugs. If there is no continuity, it means that the coil is not working properly. Another way to test an ignition coil is to use a voltmeter to see if the voltage is above 12 volts when the engine is started. If it isn’t, the coil may need to be replaced.

What to do if the ignition coil is bad

If you suspect that your ignition coil is bad, there are a few things that you can do to test the theory. Some of these tests are easy to do and don’t require any special tools or expertise. Others may require a bit of extra effort, but will give you a more definitive answer.

The first test that you can do is to remove the spark plugs and check for continuity between the terminals on the coil. If there’s no continuity, then it’s probably bad and needs to be replaced.

Another test that you can perform is to disconnect the battery cable and crank the engine over a few times with the key off. If the coil fires up when you crank the engine over, then it’s probably good. However, if the coil doesn’t fire up even after being cranked over many times, then it’s likely bad and needs to be replaced.


A car’s ignition coil is responsible for starting the engine. It requires a healthy spark to ignite the fuel in the cylinders and get your car moving. If you’re having trouble starting your car, there are a few things you can do to check if your ignition coil is working properly. Check all of your vehicle’s electrical systems one by one, as sometimes problems with one system will cause another system to fail. If none of these fixes work or if you suspect that something more serious is wrong with your car’s ignition coil, don’t hesitate to take it into a mechanic for inspection.