Ignition Coil Troubles: Understanding the P0355 Code

Ignition Coil Troubles Deciphering The P0355 Code

If you’re experiencing engine troubles and have received the P0355 code, it’s likely that your ignition coil is the culprit.

Ignition coils are responsible for converting the battery’s low voltage into the high voltage required to ignite the fuel in your engine.

When an ignition coil fails, it can cause a variety of problems, including misfires, rough idling, and stalling.

A car with open hood, smoke rising from engine, diagnostic tool plugged in, displaying P0355 code

The P0355 code specifically indicates a malfunction in the ignition coil “E” circuit, which can be caused by a variety of issues, including a faulty coil, damaged wiring, or a problem with the engine control module.

It’s important to address this issue promptly, as a malfunctioning ignition coil can cause damage to other components in your engine and decrease your vehicle’s overall performance.

In this article, we’ll explore the common causes of ignition coil troubles, how to diagnose the issue, and steps you can take to fix it.

Understanding the P0355 Code

If you’re experiencing ignition coil troubles, chances are you’ve encountered the P0355 code.

This code refers to a malfunction in the primary or secondary circuit of ignition coil number 5.

It’s important to understand what this code means in order to properly diagnose and fix the issue.

When the P0355 code is triggered, your vehicle’s engine control module (ECM) will illuminate the check engine light.

You may also notice symptoms such as rough idling, poor acceleration, or a decrease in fuel efficiency.

To diagnose the issue, you’ll need to use a scan tool to retrieve the diagnostic trouble codes (DTCs) stored in the ECM.

Once you’ve identified the P0355 code, you’ll need to inspect the ignition coil, wiring, and connectors for any signs of damage or corrosion.

If no visible issues are found, you can use a multimeter to test the resistance of the ignition coil and its wiring.

The resistance values should be within the manufacturer’s specifications.

If the values are outside of the acceptable range, the ignition coil may need to be replaced.

It’s important to note that the P0355 code can also be triggered by issues with the ECM, such as a faulty driver circuit or a malfunctioning power supply.

If you’ve ruled out issues with the ignition coil and its wiring, it may be necessary to perform further testing on the ECM.

In summary, the P0355 code indicates a problem with the ignition coil circuit for cylinder 5.

Proper diagnosis and repair of the issue will require inspecting and testing the ignition coil, wiring, and connectors, as well as potentially testing the ECM.

Common Symptoms of Ignition Coil Failure

Sparks fly from a malfunctioning ignition coil, causing engine misfires and rough idling.

Check engine light illuminates with P0355 code

If you are experiencing issues with your vehicle’s ignition system, it could be due to a faulty ignition coil.

Here are some common symptoms of ignition coil failure:

Engine Misfires

One of the most common symptoms of a failing ignition coil is engine misfires.

Misfires occur when there is a lack of spark in one or more of the cylinders.

This can cause a rough running engine and can even cause the engine to stall.

Rough Idling

Another symptom of a failing ignition coil is rough idling.

This occurs when the engine is running at low RPMs and can cause the vehicle to shake or vibrate.

This symptom is often accompanied by a check engine light.

Reduced Fuel Efficiency

A failing ignition coil can also cause reduced fuel efficiency.

This is because the engine is not running as efficiently as it should be, which can cause the vehicle to use more fuel than necessary.

If you are experiencing any of these symptoms, it is important to have your vehicle inspected by a qualified mechanic.

Ignition coil failure can lead to more serious issues if left untreated.

Diagnosing the P0355 Code

Spark plugs, wires, and ignition coil laid out on a workbench with diagnostic tools and a code reader displayed nearby

If your vehicle’s check engine light is on and you’ve received a P0355 code, it’s important to diagnose the issue as soon as possible.

Ignition coil troubles can lead to poor engine performance, reduced fuel efficiency, and even engine damage if left unchecked.

Here are some steps you can take to diagnose the P0355 code.

Visual Inspection

The first step in diagnosing the P0355 code is to perform a visual inspection of the ignition system.

Check for any obvious signs of damage, such as cracks in the ignition coils or damaged wiring.

Make sure all connections are secure and free of corrosion.

If you notice any problems during the visual inspection, address them before moving on to further testing.

Electrical Testing

Next, you’ll need to perform some electrical testing to determine the cause of the P0355 code.

Use a multimeter to test the resistance of each ignition coil. The resistance should be within the manufacturer’s specifications.

If any of the ignition coils have a resistance outside of the acceptable range, they may need to be replaced.

You should also test the wiring and connectors for each ignition coil.

Check for continuity and voltage drop across the wires and connectors.

If you find any issues, repair or replace the affected components as necessary.

Onboard Diagnostics

Finally, you can use onboard diagnostics to further diagnose the issue.

Use a scan tool to access the vehicle’s onboard computer and read any stored trouble codes.

Look for any additional codes related to the ignition system, such as misfire codes.

This can help you pinpoint the exact cause of the P0355 code.

In addition, you can use the scan tool to perform a power balance test.

This test will help you determine if any of the cylinders are misfiring.

If you find a misfiring cylinder, you can focus your diagnosis on that specific cylinder and ignition coil.

By following these steps, you can diagnose the P0355 code and determine the cause of your ignition coil troubles.

Remember to address any issues as soon as possible to prevent further damage to your vehicle’s engine.

Repair and Replacement

A car hood open, with tools scattered around.

A mechanic holding an ignition coil, inspecting it closely. A diagnostic code displayed on a handheld device

Ignition Coil Repair

If you have determined that your ignition coil is the culprit behind the P0355 code, you have a few options for repair.

First, you can attempt to repair the coil itself.

This may involve replacing damaged or worn components, such as the wiring or connectors.

However, if the coil is severely damaged or has internal issues, it may be best to replace it entirely.

Another option is to have the coil professionally repaired.

This can be a cost-effective solution if you have a high-quality coil that is worth salvaging.

However, be sure to choose a reputable repair service to ensure that the coil is repaired correctly.

Associated Components

It’s important to also check the associated components when repairing or replacing an ignition coil.

This includes the spark plugs, spark plug wires, and other components that can affect the performance of the ignition system.

If the spark plugs are worn or damaged, they should be replaced along with the ignition coil.

Be sure to choose high-quality spark plugs that are compatible with your vehicle’s make and model.

The spark plug wires should also be inspected for wear or damage.

If they are in poor condition, they should be replaced along with the coil and spark plugs.

Overall, repairing or replacing an ignition coil can be a straightforward process, but it’s important to take the time to properly diagnose the issue and ensure that all associated components are in good condition.

By doing so, you can avoid further issues and keep your vehicle running smoothly.

Preventative Measures and Maintenance

A car with an open hood, mechanic diagnosing ignition coil issues with a code reader and multimeter.

Tools and replacement parts nearby

To avoid ignition coil troubles and the P0355 code, it is important to perform regular maintenance on your vehicle.

Here are some preventative measures you can take:

  • Keep your engine clean: Dirt and debris can cause damage to your ignition coils, so it is important to keep your engine clean.

    Regularly wash your engine with a mild detergent and water, and avoid using high-pressure water or steam cleaners.

  • Replace spark plugs and wires: Worn or damaged spark plugs and wires can cause ignition coil problems, so it is important to replace them regularly.

    Check your owner’s manual for recommended replacement intervals.

  • Use high-quality fuel: Poor-quality fuel can cause misfires and other engine problems that can damage your ignition coils.

    Use high-quality fuel and avoid filling up at gas stations with a reputation for selling low-quality fuel.

  • Check your battery: A weak or dead battery can cause voltage fluctuations that can damage your ignition coils.

    Check your battery regularly and replace it if necessary.

  • Avoid overloading your vehicle: Overloading your vehicle can put extra strain on your engine, which can cause ignition coil problems.

    Make sure you are not carrying more weight than your vehicle can handle.

By following these preventative measures and performing regular maintenance on your vehicle, you can help prevent ignition coil troubles and avoid the P0355 code.

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About the author

The Motor Guy

The Motor Guy is a passionate car enthusiast with a love for troubleshooting and diagnosing all sorts of vehicle problems.

With years of experience in OBD diagnostics, he has become an expert in identifying and solving complex automotive issues.

Through, he shares his knowledge and expertise with others, providing valuable insights and tips on how to keep your vehicle running smoothly.

- 12 years experience in the automotive industry
- ASE Master Automobile Technician
- A Series: Automobile and Light Truck Certification, A9 Light Vehicle Diesel Engine Certification
- Bachelor's Degree in Information Systems