How to check ignition coils on a Subaru?
Checking the ignition coils on your Subaru is an important maintenance task that can help identify and resolve issues with your vehicle's ignition system. Ignition coils are responsible for providing the high-voltage spark that ignites the air-fuel mixture in your engine's cylinders, and if they are not functioning properly, it can lead to misfiring, poor performance, and even engine damage. In this article, we'll walk you through the steps to check your Subaru's ignition coils.
What Are Ignition Coils?
Ignition coils are an essential component of your Subaru's ignition system. They are responsible for transforming the low-voltage current from the battery into the high-voltage spark that is needed to ignite the air-fuel mixture in the engine's cylinders. Each cylinder in your Subaru's engine has its own ignition coil, and if one or more of these coils fail, it can cause misfiring, reduced engine performance, and decreased fuel efficiency.
Signs of a Failing Ignition Coil
There are several signs that may indicate a problem with your Subaru's ignition coils, including:
- Rough idling or engine misfiring
- Reduced engine power or acceleration
- Decreased fuel efficiency
- Check engine light illuminated on the dashboard
- Difficulty starting the engine
If you notice any of these symptoms, it's important to have your Subaru's ignition system checked by a qualified mechanic as soon as possible to prevent further damage to your engine.p>
How to Check Ignition Coils
Checking your Subaru's ignition coils is a relatively straightforward process that can be done with a few basic tools. Here are the steps to follow:
- Locate the ignition coils: The ignition coils on a Subaru are typically located on top of the engine, near the spark plugs.
- Visually inspect the coils: Look for any signs of damage, such as cracks, burns, or discoloration, which may indicate a problem with the coil.
- Use a multimeter: Set your multimeter to the "ohms" setting and test each ignition coil by measuring the resistance between the primary and secondary windings. The resistance should be within the manufacturer's specified range, which can be found in your Subaru's service manual.
- Perform a spark test: Remove one of the ignition coils and use a spark tester to check for a strong, consistent spark. If the spark is weak or intermittent, the coil may need to be replaced.
If you find that one or more of your Subaru's ignition coils are not functioning properly, it's important to replace them as soon as possible to prevent further damage to your engine.
Conclusion
Checking your Subaru's ignition coils is an important maintenance task that can help identify and resolve issues with your vehicle's ignition system. By following the steps outlined in this article, you can quickly and easily diagnose any problems with your Subaru's ignition coils and take the necessary steps to address them. Remember, if you're not comfortable performing this task yourself, it's always best to have a qualified mechanic handle it for you.
How much does it cost to replace ignition coils on a Subaru?
The cost to replace a Subaru ignition coil generally ranges from approximately $200 to over $800, but this can vary significantly based on the model, the specific coil, and labor rates. Parts can cost between $50 and $300 each, while labor adds to the total price. The total price depends on whether a dealership, independent mechanic, or DIY approach is used.
Cost breakdown
- Parts: A single ignition coil can cost anywhere from $50 to over $300, depending on the model and quality. Some parts are much more expensive than others.
- Labor: Professional installation adds to the cost. Labor rates can vary depending on the repair shop and the time it takes to diagnose the problem, which is important for correctly identifying the faulty coil.
- Total estimate: A general estimate for replacing one ignition coil is around $230 to $330, with labor making up a portion of this cost.
Factors that influence the cost
- Subaru model: The year, make, and model of your Subaru will influence the price of the part and labor.
- Part quality: The cost can change depending on whether you buy a genuine OEM (Original Equipment Manufacturer) part or an aftermarket part.
- Number of coils: If multiple coils are faulty, the total cost will be higher.
- Service type: The final price will vary depending on whether you choose to have the work done by a dealership, an independent shop, or perform a DIY replacement.
How to test a Subaru ignition coil?
How To Test Subaru Ignition Coils
- Scan for Trouble Codes. Use an OBD-II scanner.
- Inspect Visually. Look for cracks or damage on the coil body, corrosion on the connections, loose wires, or oil contamination.
- Swap Coils.
- Check Resistance.
- Load Test.
How do you check if the ignition coil is bad?
You can check for a bad ignition coil by visually inspecting it for cracks or using a multimeter to test its resistance against the manufacturer's specifications. Another method is to use a spark tester to see if the coil is producing a strong, blue spark while the engine is running; a weak or no spark indicates a faulty coil.
Diagnostic tests
- Spark test: Connect a spark tester to the end of the coil, ground the tester, and crank the engine. A strong, blue spark is good; a weak or non-existent spark means the coil is bad.
- Multimeter test: Disconnect the coil and set your multimeter to measure resistance (ohms).
- Measure the resistance across the coil's primary terminals and compare it to your car's manual.
- For the secondary winding, measure the resistance between the high-voltage terminal and the primary terminal. A typical range is 6,000 to 15,000 ohms, but this can vary, so check your manual for exact specifications.
- If the readings are outside the specified range, the coil is likely faulty.
Other signs of a bad ignition coil
- Difficulty starting: The engine may be slow to start or not start at all.
- Misfiring: The engine may feel like it's "stuttering" or running roughly.
- Reduced fuel efficiency: You may notice a decrease in gas mileage.
- Poor acceleration: The car may not accelerate as quickly as it should.
- Check Engine light: An OBD2 scanner can read codes like P030X (misfire) or P035X (ignition coil issue).
Can OBD2 detect a bad ignition coil?
With most modern vehicles, a faulty ignition coil is enough to turn on the Check Engine Light. If you have an OBD-II diagnostic scanner, you may see a P0351 ignition code. Of course, because all cars are different, an ineffective ignition coil may register a different code for the problem.
