Fix P0355: Mechanic’s solutions that WORKED


The code P0355: Ignition Coil “E” Primary/Secondary Circuit Malfunction
points out a fault in the ignition coil’s primary or secondary circuit, and it’s most likely caused by issues with the coil itself, wiring, or the connector.

P0355 quick overview

MeaningP0355: Ignition Coil “E” Primary/Secondary Circuit Malfunction
Is it serious?Yes, it can affect the vehicle’s performance, fuel efficiency, and emissions.
Possible causes– Damaged or faulty ignition coil
– Corroded terminals on the coil connector
– Wiring issues related to the ignition coil
– Faulty or damaged connectors
– Issues with the Powertrain Control Module (PCM)
How to diagnose?Scan for Codes: Always start by scanning the vehicle to confirm the presence of the P0355 code and check for any other related codes.
Visual Inspection: Check the ignition coil, its connectors, and wiring for any visible damages or signs of wear.
Check the Wiring and Connector: Inspect for corroded terminals or damaged connectors. Ensure the wires are in the correct order if they’ve been tampered with.
Test the Ignition Coil: Use a multimeter or oscilloscope to test the ignition coil’s functionality. Compare the waveform or readings to the manufacturer’s specifications.
Swap Coils: If possible, swap the suspected faulty coil with a known working coil from another cylinder. If the fault code changes to the new cylinder, the coil is the issue.
Check the PCM: In rare cases, the PCM might be the cause. Ensure it’s functioning correctly and isn’t sending incorrect signals to the ignition coil.
Overview of P0355 trouble code

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How to fix P0355 – learn from mechanics

I looked into P0355 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Mercedes

Vehicle Information

  • 2006 Mercedes-Benz CLK350 3.5L

Issue + Repair History

  • Intermittent CEL (Check Engine Light) and roughness.
  • Previous repair: Replaced ignition coil and spark plug for cylinder #5 with OE MB parts. Cleared the fault code and did a rotor sensor adaption.
  • Fault codes: 1019 (control line to ignition coil) and Po355 (ignition coil #5).

Suggestions from Community

  • Move the new coil to another cylinder and check if the problem follows.
  • Check the spark plugs from #5 and either replace or move them to another cylinder.
  • Check for rodent damage to the wiring harness.
  • Invest in a Mercedes SDS (Star Diagnostic System) for accurate diagnostics.
  • Confirm the correlation between the scanner’s code description and the actual fault.

Final Fix

  • The scanner’s code description was incorrect. The correct correlation was established between PO355 and 1019.
  • Replaced coil #4 after confirming the scanner’s error.
  • The vehicle has since covered 2,000 miles without any issues.

Case #2: Toyota

Vehicle Information

  • 2006 Toyota RAV4 Sport 3.5L

Issue + Repair History

  • Vehicle sets specific codes immediately after erasing.
  • No drivability symptoms except cruise control being disabled due to the mentioned codes.
  • Fault codes: P0301306 (Misfires all cylinders), P0355, P1578, C1223, C1241, C1201.

Suggestions from Community

  • Check the charging system and consider a potential issue with the ignition coil for cylinder 5.
  • Inquire about any testing that has been done.
  • Replace ignition coil for cylinder 5. One bad coil can affect others.
  • Replace the brake light switch to address the ‘C’ codes.

Final Fix

  • Replaced the coil for cylinder 5 and erased codes.
  • After driving about 60 miles, no codes returned.
  • Fixing the P0355 with the coil seemed to resolve all other codes.

Case #3: Ford

Vehicle Information

  • 2006 Ford Five Hundred SEL 3.0L

Issue + Repair History

  • Vehicle has a P0355 fault code.
  • After clearing the ignition circuit malfunction, the vehicle runs well until the check engine light returns and it starts running rough again, specifically cylinder #5.
  • Fault code: P0355.
  • Recent engine tune performed.

Suggestions from Community

  • Check the wires going from PCM to the ignition coil.
  • Consider replacing the ignition coil or moving it to another cylinder.
  • P0355 typically indicates a primary circuit in cylinder number 5 coil pack. If not addressed, it might damage the transistor in the PCM.
  • Misfire might be due to the computer shutting power to the coil and fuel injector to prevent damage to the transistor.
  • Swap the #5 ignition coil with another cylinder to see if the issue persists or follows the coil.
  • Check pin fit and harness integrity at the #5 Ignition Coil connector.
  • Use a Noid light plugged into the ignition coil connector to test for proper voltage and trigger signal from the PCM.

Final Fix

  • Replaced 2 more ignition coils (one OEM and one from Carquest).
  • Also changed the coil on cylinder #4.
  • The check engine light has been off and the vehicle runs well.

Case #4: Volvo

Vehicle Information

  • 1999 Volvo V70 2.4L

Issue + Repair History

  • Vehicle stalls and has a slight rough idle when cold, lasting about 20-30 seconds.
  • Fault codes: P1081 (unknown description), P0350 (ignition coil primary/secondary circuit malfunction), and P0355 (ignition coil e primary/secondary circuit malfunction).
  • No information available on P1081.
  • Issues with the scan tool (GENYSIS) showing incorrect PCM ID.

Suggestions from Community

  • Ensure the car has Volvo spark plugs.
  • Check cam or crank sensor.
  • Check for vacuum leaks.
  • Check the wires from PCM to ignition coil and consider replacing or moving the coil.
  • Swap the #5 ignition coil with another cylinder to see if the issue persists or follows the coil.
  • Check the charging system and consider a software upgrade for the throttle.
  • Tighten the connection at the antenna ring for the ignition key or consider replacing the antenna ring.
  • Check for oil in the plug wells and inspect the spark plugs.

Final Fix

  • Replaced the #5 coil and installed a new set of spark plugs.
  • Had the computer reflashed.
  • After the repairs, the vehicle passed the North Carolina state inspection and has been running well.

Case #5: Honda

Vehicle Information

  • 2002 Honda Civic EX 1.7L

Issue + Repair History

  • Vehicle came in with a crank sensor code.
  • Corroded terminals were found on the connector.
  • The technician ordered new terminals but forgot the order of the wires.
  • The wiring diagram only provided terminal numbers which weren’t on the connector.
  • The technician connected the new terminals but the vehicle still showed codes.
  • The technician verified power and ground to the connector but was uncertain about the signal wire’s correct terminal.

Suggestions from Community

  • Clarification on the fault code, suggesting it might be P0335 (CKP sensor no signal) instead of P0355.
  • The order of the wires in the connector:
    1. Blue (sensor output)
    2. Brown/Yellow (ground)
    3. Yellow/Black (circuit D04)
  • A suggestion that there might be two problems, leading to the MIL light still being on.

Final Fix

  • The crank sensor was found to be faulty.
  • Corrosion was observed on the sensor’s terminal tabs.
  • After replacing the crank sensor, a perfect waveform was observed.
  • The technician confirmed that the original fault code should have been P0335.
  • The bolt on the crank pulley posed some challenges during the repair.
  • The technician thanked community members for their assistance, especially Edgar for verifying the wire order on an actual car.

How to diagnose P0355

I made you an overview of solving this DTC, based on all the advice that was suggested by certified mechanics to address this issue in previously mentioned service cases.

  • Check the Wiring and Connector: In multiple cases, corroded terminals or connectors were identified as the root cause. Always inspect the wiring and connectors for any signs of damage or corrosion.
  • Verify Wire Order: If connectors or terminals are replaced, ensure that the wires are placed in the correct order. If uncertain, consult a wiring diagram or seek advice from fellow technicians.
  • Replace the Crank Sensor: If there are issues with the waveform or if corrosion is observed on the sensor’s terminals, consider replacing the crank sensor.
  • Use Reliable Diagnostic Tools: Ensure that the diagnostic tools being used provide accurate and reliable information. Some technicians faced challenges due to misleading or incomplete data from their diagnostic tools.
  • Consider Multiple Faults: If the issue persists after addressing the identified problem, consider the possibility of multiple faults or underlying issues that might be triggering the fault code.

Free PDF: How to choose OBD2 scanner

buyers guide popup

I’ve made you a free PDF to choose the OBD2 scanner in 5 minutes.

✅ Which OBD2 scanner is best?
✅ Which type should you get (DIY, Pro, Hobby)
✅ What is the best scanner for the exact brand/feature (e.g best for BMW)
✅ How to get a Bi-Directional tool for as cheap as $40
✅ Discount coupons for scanners

PDF is 100% free and it is designed to help you pick a scanner in less than a few minutes! Not a boring 50-page guide. 

Just tell me where to send it.

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