P0355
UniversalIgnition Coil E Primary/Secondary Circuit Malfunction
Medium SeverityThis code indicates an electrical fault in the primary or secondary circuit of ignition coil E. The ignition coil is responsible for generating the high voltage spark needed to ignite the fuel-air mixture in a cylinder, so a malfunction will lead to a misfire in the affected cylinder.
⚠️ Before You Begin (Safety First)
Always disconnect the negative battery terminal before performing any electrical work on your vehicle. Ensure the engine is cool to the touch before working on engine components. High voltage is present in the ignition system, so avoid contact with spark plug wires and coils while the engine is running.
Common Symptoms
- Check Engine Light illuminated
- Engine misfire
- Rough idle
- Reduced engine power
- Poor fuel economy
- Engine hesitation or stumbling during acceleration
Common Causes
- Faulty ignition coil (Coil E)
- Damaged or corroded wiring to ignition coil E
- Loose or poor electrical connection to ignition coil E
- Faulty Engine Control Module (ECM) - less common
Frequently reported on: General/Universal
Diagnostic Steps
- Use an OBD-II scanner to confirm the P0355 code and check for any other related misfire codes (P030X).
- Locate ignition coil E. (Cylinder numbering varies by manufacturer; consult your vehicle's service manual.)
- Inspect the wiring harness and connectors for ignition coil E for any visible damage, corrosion, or loose connections.
- Swap ignition coil E with a known good coil from another cylinder (e.g., Coil A). Clear the codes and run the engine to see if the misfire code moves to the new cylinder (e.g., P0351 for Coil A) or if P0355 returns.
- If the code moves, replace the faulty ignition coil. If P0355 returns and does not follow the coil, the issue is likely with the wiring or the ECM.
- After replacement, clear the codes and perform a test drive to ensure the issue is resolved.
👨🔧 When to Call a Professional
If diagnostic steps confirm the coil is faulty and you replace it, but the misfire or P0355 code returns, it's time to consult a professional mechanic. This could indicate a deeper issue with the vehicle's wiring harness, the Engine Control Module (ECM), or other related sensors that require specialized diagnostic tools.
Commonly Asked Questions
What does 'Ignition Coil E' refer to?
Ignition Coil E refers to the fifth cylinder in the engine's firing order. The exact cylinder it corresponds to (e.g., cylinder 5, cylinder 6, etc.) depends on the specific vehicle manufacturer and engine configuration. You'll need to consult your vehicle's service manual for precise cylinder identification.
Can I drive with a P0355 code?
It is not recommended to drive for extended periods with a P0355 code. A persistent misfire can lead to significant engine damage, including catalytic converter failure, due to unburnt fuel entering the exhaust system. Drive minimally and get it repaired as soon as possible.
How do I test an ignition coil?
You can test an ignition coil using a multimeter to check the resistance of its primary and secondary windings (refer to your vehicle's specifications). A more practical DIY test is often to swap the coil with a known good one from another cylinder and see if the misfire code follows the coil.
Why did my ignition coil fail?
Ignition coils can fail due to several reasons, including normal wear and tear over time, exposure to excessive heat, voltage spikes, or internal short circuits. Sometimes, faulty spark plugs or spark plug wires can also put additional strain on the coil, leading to premature failure.
Do I need to replace all ignition coils if one fails?
Typically, you only need to replace the specific coil that has failed. However, if your vehicle has high mileage or if multiple coils are starting to fail around the same time, it might be a good idea to consider replacing them as a set or proactively replacing other older coils to prevent future issues.