DTC P0350 Ignition Coil Primary/Secondary Circuit Malfunction

Troubleshoot On-Board Diagnostic Trouble Codes. As a Certified Automotive Technician and an Automotive Enthusiast, my goal is to provide you with valuable insights and practical guidance. In this article, we’ll dive into the world of On-Board Diagnostic Trouble Code P0350, which indicates an Ignition Coil Primary/Secondary Circuit Malfunction. By the end of this comprehensive guide, you’ll understand the significance of this code, be able to identify its symptoms, comprehend its potential causes, learn how to diagnose the issue, and, most importantly, discover effective strategies for fixing it.

1. What does P0350 code mean?

Let’s begin by decoding the meaning of DTC P0350. In the realm of automotive diagnostics, “P0350” is a universal code used by your vehicle’s onboard computer (OBD-II system) to communicate a specific issue. The “P” designates it as a Powertrain-related problem, typically linked to the engine or transmission. The “0350” is the unique trouble code indicating an Ignition Coil Primary/Secondary Circuit Malfunction.

In simple terms, this trouble code serves as a warning sign that there’s a malfunction in the primary or secondary circuit of one or more ignition coils. Ignition coils play a critical role in generating the high-voltage spark needed to ignite the air-fuel mixture in the engine’s cylinders.

2. What are the causes of DTC P0350?

Now, let’s explore the potential causes behind DTC P0350:

  • Faulty Ignition Coil: One or more ignition coils may be malfunctioning, leading to circuit issues.
  • Wiring or Connector Problems: Damaged, corroded, or loose wiring and connectors can disrupt the electrical connection to the ignition coils.
  • Faulty Spark Plugs: Worn or damaged spark plugs can overload the ignition coils and lead to circuit malfunctions.
  • Power Supply Issues: Problems with the power supply to the ignition coil circuit can result in malfunctions.
  • ECU (Engine Control Unit) Malfunction: In some cases, issues with the engine control unit can affect the ignition coil circuit.

3. What are the symptoms of DTC P0350?

Recognizing the symptoms associated with this trouble code is crucial for diagnosis. Common signs of DTC P0350 may include:

  • Check Engine Light (CEL): The most noticeable indicator is the illumination of the check engine light on your dashboard.
  • Engine Misfires: You may experience engine misfires, rough idling, or poor overall engine performance.
  • Reduced Power: The vehicle may lack power and not accelerate as expected.
  • Stalling: The engine may stall intermittently due to ignition coil circuit malfunctions.

4. How to diagnose DTC P0350?

Diagnosing DTC P0350 requires a systematic approach. Here’s a step-by-step guide:

  • Scan the Code: Use an OBD-II scanner to retrieve the trouble code and confirm the issue.
  • Inspect Wiring and Connectors: Carefully examine the wiring and connectors related to the ignition coil circuit for damage, corrosion, or loose connections.
  • Test Ignition Coils: Test the ignition coils individually using a multimeter to check their resistance and ensure they are within specifications.
  • Check Spark Plugs: Inspect and replace spark plugs if necessary, as they can affect ignition coil performance.
  • Verify Power Supply: Ensure that the power supply to the ignition coil circuit is stable and within the specified range.
  • Check ECU: If all else fails, consider checking the engine control unit for malfunctions that may affect the ignition coil circuit.

5. How to fix DTC P0350 problem?

Now, let’s delve into effective strategies for fixing DTC P0350:

  1. Replace Faulty Ignition Coils: If one or more ignition coils are malfunctioning, replace them with high-quality replacements.
  2. Repair or Replace Wiring and Connectors: If you find damaged wiring or connectors, repair or replace them as necessary.
  3. Replace Spark Plugs: Worn or damaged spark plugs should be replaced to prevent overloading of the ignition coils.
  4. Check Power Supply: Ensure that the power supply to the ignition coil circuit is stable and within the specified range.
  5. Clear the Trouble Code: After completing the repairs, use your OBD-II scanner to clear the trouble code.
  6. Test Drive: Take your vehicle for a test drive to ensure that the issue has been successfully resolved and that the check engine light remains off.


In conclusion, DTC P0350, indicating an Ignition Coil Primary/Secondary Circuit Malfunction, is a challenge that can affect your vehicle’s performance. However, armed with the knowledge and guidance provided in this guide, you’re well-prepared to diagnose and address the issue effectively. Always prioritize safety, and if you’re uncertain, seek professional assistance. Happy troubleshooting, fellow automotive enthusiasts!