how to test ignition coil with multimeter

by:Haiyan     2023-07-04

How to Test Ignition Coil with a Multimeter


Testing your ignition coil is crucial to ensure that it is functioning properly. A faulty ignition coil can cause misfires, poor fuel efficiency, and even prevent your vehicle from starting. In this article, we will guide you through the process of testing an ignition coil using a multimeter. With the help of a multimeter, you can easily check the primary and secondary windings of the coil to determine if it needs to be replaced. Follow these steps and gain the knowledge to diagnose any issues with your ignition coil.


1. Understanding the Function of an Ignition Coil

2. Choosing the Right Multimeter

3. Testing the Primary Windings

4. Testing the Secondary Windings

5. Interpreting the Results

Understanding the Function of an Ignition Coil:

The ignition coil is a crucial component of the ignition system in your vehicle. Its primary function is to convert the low voltage from your battery into high voltage required by the spark plugs to ignite the air-fuel mixture in the combustion chamber. The coil consists of primary and secondary windings wrapped around a core. Over time, the primary or secondary windings may wear out, leading to a malfunctioning coil.

Choosing the Right Multimeter:

To effectively test your ignition coil, you will need a digital multimeter capable of measuring resistance and voltage. Ensure that your multimeter is set to measure resistance (ohms) and has a high voltage setting for accurate readings. If your meter does not have an auto-range feature, set it to a high resistance range such as 200 ohms. Keep in mind that each multimeter may have slightly different settings and functions, so it's important to consult the user manual for specific instructions.

Testing the Primary Windings:

The primary windings of an ignition coil are responsible for generating the magnetic field required for voltage induction in the secondary windings. To test the primary windings, follow these steps:

1. Disconnect the ignition coil from the power source and any associated wires.

2. Set your multimeter to the ohms () setting.

3. Touch the multimeter leads to the positive and negative terminals of the ignition coil. Ensure that there is good contact between the leads and the terminals.

4. Read the resistance value displayed on your multimeter. The typical resistance for primary windings ranges from 0.4 to 2 ohms for most coils. Compare this value to the specified resistance range provided by the manufacturer. If the resistance is significantly outside the range, it indicates a fault in the primary windings.

Testing the Secondary Windings:

The secondary windings of the ignition coil are responsible for stepping up the voltage from the primary windings and delivering it to the spark plugs. Follow these steps to test the secondary windings:

1. Consult your vehicle's service manual to determine the appropriate secondary resistance values for your specific ignition coil. These values may differ depending on the make and model of your vehicle.

2. Keeping the multimeter set to the ohms () setting, connect one lead to the positive terminal of the coil and the other to the spark plug terminal.

3. Read the resistance value displayed on the multimeter. Compare this reading to the specified range provided in your vehicle's service manual. If the resistance exceeds or falls below the recommended range, it indicates a fault in the secondary windings.

Interpreting the Results:

Once you have conducted the tests, compare the resistance values obtained to those specified by the manufacturer. If any of the resistance values are significantly outside the recommended range, it is likely that your ignition coil is faulty and needs to be replaced. In such cases, consult a professional mechanic or refer to your vehicle's service manual for further guidance on selecting and installing a new ignition coil.


Testing your ignition coil with a multimeter is a straightforward process that can help you identify any faults and maintain the efficiency of your vehicle's ignition system. By following the steps outlined in this article, you can easily test both the primary and secondary windings of the coil, allowing you to diagnose and resolve any potential issues. Regularly testing your ignition coil is a good practice that can prevent major engine problems and ensure smooth running of your vehicle.

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