01 The Future of Autonomous Vehicles • 02 P0300: Random or Multiple Cylinder Misfire Detected – Cause… • 03 Decoding the Engine Control Unit (ECU): Inputs, Outputs, an… • 04 Hackers Can Now Steer Your Car Remotely And Here’s How to S… • 05 The $30 Device That's Making Car Thieves Invisible to Police • 06 What Causes Your RPM to Go Up and Down When You Brake? Find… • 07 How Adaptive Cruise Control Actually Works • 08 Gearing Up: Manual vs. Automatic Transmissions in Modern Ca… • 09 How to Prevent Catalytic Converter Failure and Maintain Its… • 10 Thinking of Upgrading to LED Headlights? Here's What You Mu… •

DTC codes / P03xx · Ignition system and misfire / P0361

P0361Ignition Coil 'K' Primary/Secondary Circuit

P0361 indicates that the powertrain control module (PCM) has detected a fault in the primary or secondary circuit of ignition coil 'K', which is one of the individual coils in a coil-on-plug or distributorless ignition system. The PCM monitors the coil's electrical behavior and sets this code when the circuit's resistance, voltage drop, or feedback signal falls outside the expected range, often resulting in a misfire on the affected cylinder.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaIgnition system and misfire

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms at first
  • Rough idle or engine vibration, especially when the engine is cold or under light load
  • Noticeable misfire that may feel like a stumble or hesitation during acceleration
  • Reduced fuel economy due to incomplete combustion in the affected cylinder
  • A flashing check engine light if the misfire is severe enough to damage the catalytic converter
  • Loss of power or sluggish acceleration when the faulty coil fails to fire under load

Common causes, most likely first

  1. Faulty ignition coil 'K' with an open or shorted primary or secondary winding
  2. Worn or damaged spark plug or spark plug boot causing excessive resistance in the secondary circuit
  3. Corroded, loose, or damaged electrical connector at the coil or PCM
  4. Chafed or broken wiring in the coil's primary circuit, often near the engine harness
  5. Failed ignition coil driver inside the PCM (less common but possible)
  6. Moisture intrusion into the coil or connector, leading to intermittent misfires
  7. Aftermarket or incorrect coil that does not meet the original resistance specifications

How to diagnose and fix it

  1. Scan all modules for stored and pending codes, and record freeze-frame data to confirm the misfire count on the affected cylinder
  2. Inspect the coil 'K' connector and wiring for corrosion, looseness, or chafing, and repair as needed
  3. Swap ignition coil 'K' with a known-good coil from another cylinder and see if the misfire moves with the coil
  4. Remove and inspect the spark plug and boot for wear, carbon tracking, or incorrect gap, and replace if suspect
  5. Measure the primary and secondary resistance of coil 'K' with a multimeter and compare to the manufacturer's specification
  6. Perform a spark test or use an oscilloscope to check for consistent secondary ignition voltage
  7. If the coil and wiring test good, check for a faulty PCM driver by testing the control circuit with a noid light or oscilloscope

What a coil code often hides

  • A P0361 can be set by a worn spark plug that increases secondary resistance, causing the coil to overheat and fail, so always replace plugs when replacing a coil.
  • Intermittent misfires that set P0361 only under load often trace to a coil that tests fine at idle but breaks down when hot, so a simple resistance check may not be conclusive.
  • The PCM may set P0361 without a companion misfire code if the fault is in the coil's feedback circuit rather than the firing circuit, so don't assume the coil itself is bad.
  • Corrosion inside the coil boot or connector can mimic a failed coil, and cleaning or replacing the boot often resolves the code without a new coil.
  • A weak battery or charging system can cause low voltage to the coils, triggering P0361 and other coil codes simultaneously, so check system voltage first.

Can I keep driving with P0361?

You can usually drive with P0361 if the check engine light is steady and the engine runs smoothly, but avoid heavy acceleration or towing until the fault is repaired. If the light flashes or the engine misfires severely, stop driving to prevent catalytic converter damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage