P0355 Code: Here's How to Solve It Fast

The P0355 trouble code is a diagnostic error code that indicates a problem with the ignition coil "E" primary/secondary circuit. This code is logged by the vehicle's Powertrain Control Module (PCM) when it detects an issue with the ignition coil associated with cylinder number 5. The ignition coil is crucial for converting battery voltage into the high voltage needed to create a spark at the spark plug, which ignites the air-fuel mixture in the engine's combustion chamber. When this system fails, it can lead to various performance issues, including misfires, poor acceleration, and increased emissions.

P0355 Code Meaning	P0355 Code Common Causes
Ignition Coil "E" Primary/Secondary Circuit Malfunction	Defective ignition coil for cylinder #5
Electrical issue with the ignition coil circuit	Damaged wiring or connectors
Faulty Powertrain Control Module (PCM)	Worn or damaged spark plugs
Open or shorted circuits in the ignition system	Vacuum leaks affecting engine performance

Symptoms of P0355 Code

When the P0355 code is triggered, vehicle owners may notice several symptoms that indicate a problem with the ignition system:

• Check Engine Light (CEL): The most common symptom is an illuminated CEL on the dashboard.
• Rough Idling: The engine may idle unevenly or roughly due to misfires.
• Engine Misfires: The vehicle may experience intermittent or constant misfiring, particularly in cylinder #5.
• Poor Acceleration: Drivers may feel a lack of power or sluggish acceleration when attempting to accelerate.
• Increased Emissions: A malfunctioning ignition coil can lead to higher emissions due to incomplete combustion.

Technical Explanation of P0355 Code

The P0355 code specifically refers to issues within the ignition coil circuit for cylinder #5. Each cylinder in an internal combustion engine typically has its own ignition coil that is responsible for generating the necessary spark. The PCM monitors the performance of these coils and their circuits. If it detects that the signals from the ignition coil "E" are outside of expected parameters—either too low or too high in resistance—it will trigger this code.

Step-by-Step Diagnosis

Diagnosing a P0355 code involves several steps:

1. Retrieve Codes: Use an OBD-II scanner to confirm that P0355 is present and check for any additional codes that may provide context.
2. Visual Inspection: Inspect the wiring and connectors associated with the ignition coil for any signs of damage, corrosion, or loose connections.
3. Coil Testing: Test the ignition coil using a multimeter to measure resistance across its terminals. Compare these readings with manufacturer specifications.
4. Spark Plug Inspection: Check the spark plug connected to cylinder #5 for wear or damage; replace if necessary.
5. Circuit Testing: Use a wiring diagram to trace the circuit from the PCM to the ignition coil and test for continuity and shorts.
6. PCM Evaluation: If all other components are functioning correctly, consider testing or replacing the PCM as a last resort.

Solution Methods

Once you have diagnosed the cause of the P0355 code, you can proceed with repairs:

1. Replace Ignition Coil

If testing reveals that the ignition coil is defective:

• Remove the old ignition coil from cylinder #5.
• Install a new ignition coil, ensuring all connections are secure.
• Clear any stored codes and test drive to verify repair.

2. Repair Wiring Issues

If damaged wiring or connectors are found:

• Repair any frayed or broken wires using solder and heat shrink tubing.
• Replace any corroded connectors with new ones.
• Ensure all connections are tight and free from dirt or corrosion.

3. Replace Spark Plugs

If spark plugs are worn out:

• Remove old spark plugs using a spark plug socket.
• Inspect for wear; replace if necessary.
• Reinstall new spark plugs with proper torque specifications.

4. Address Vacuum Leaks

If vacuum leaks are suspected:

• Inspect vacuum lines and intake manifold gaskets for cracks or disconnections.
• Use smoke testing if necessary to identify hard-to-find leaks.
• Repair or replace any damaged components.

Cost Estimates

The cost of repairs related to a P0355 code can vary widely based on labor rates and parts prices:

• Ignition Coil Replacement: $100 - $300 (parts and labor)
• Wiring Repairs: $50 - $150 (depending on extent of damage)
• Spark Plug Replacement: $20 - $100 (depending on type of plugs used)
• Vacuum Leak Repairs: $50 - $200 (depending on severity)

Warnings and Recommendations

It’s important to address P0355 codes promptly as they can lead to more significant engine problems over time. Ignoring this code can result in:

• Increased fuel consumption due to inefficient combustion.
• Potential damage to other engine components from prolonged misfiring.
• Higher emissions leading to potential failure during emissions testing.

Always consult your vehicle’s service manual for specific diagnostic procedures and specifications related to your make and model.

Frequently Asked Questions About P0355

• What does a P0355 code mean?
  The P0355 code indicates a malfunction in the primary/secondary circuit of ignition coil "E," which corresponds to cylinder #5.
• Can I drive my car with a P0355 code?
  While it is possible to drive with this code, it is not recommended as it may lead to further engine damage.
• How serious is a P0355 code?
  This code is considered serious as it affects engine performance and can lead to additional issues if not addressed.
• What could cause a P0355 code?
  Common causes include a faulty ignition coil, damaged wiring, bad spark plugs, or issues with the PCM.
• How do I fix a P0355 code?
  Fixing this code typically involves replacing faulty components like the ignition coil or spark plugs and repairing any damaged wiring.
• Is it safe to replace an ignition coil myself?
  If you have basic mechanical skills and tools, replacing an ignition coil can be done safely at home.
• How much does it cost to fix a P0355 code?
  The cost can range from $100 to $300 depending on whether you need parts replaced or wiring repaired.
• Should I take my car to a mechanic for a P0355 code?
  If you're unsure about diagnosing or fixing it yourself, it's best to consult a professional mechanic.

In conclusion, understanding and addressing the P0355 trouble code is crucial for maintaining your vehicle's performance. By following proper diagnostic procedures and performing necessary repairs, you can ensure your vehicle runs smoothly while avoiding costly future repairs. Always prioritize safety and consult professionals when in doubt about your vehicle's condition.