If your check engine light is on and you’re seeing a P1339 code causes engine misfire, it’s not just a warning it’s a sign that something specific in your ignition system isn’t delivering spark where and when it should. That missing spark leads to unburned fuel, rough idling, hesitation under acceleration, or even stalling. You’re likely reading this because your car feels “off,” the scanner pulled P1339, and now you need to know what’s actually broken not just what the code says.

What does P1339 actually mean?

P1339 is a manufacturer-specific diagnostic trouble code (DTC) used by Honda and Acura vehicles. It stands for “Ignition Coil ‘C’ Primary/Secondary Circuit Malfunction.” In plain terms: the vehicle’s computer detected an issue with the electrical signal going to or returning from the third ignition coil (coil “C”) in the firing order. That coil powers cylinder #3. When it fails or loses connection, cylinder #3 stops firing properly, which directly causes an engine misfire.

Why does P1339 cause an engine misfire?

A misfire happens when one or more cylinders fail to combust fuel correctly. With P1339, the root cause is almost always related to the ignition coil for cylinder #3 not fuel delivery or compression. The coil may be cracked, internally shorted, or have corroded terminals. Wiring between the coil and the engine control unit (ECU) could be frayed or damaged. Even a loose or dirty connector at the coil pack can interrupt the signal enough for the ECU to log P1339 and cut power to that cylinder to protect the catalytic converter.

What symptoms go with P1339?

It’s rare for P1339 to show up without noticeable drivability issues. If you’re only seeing the code and no symptoms, double-check the scan tool some generic OBD2 readers misreport or misinterpret Honda-specific codes like P1339.

Common mistakes people make diagnosing P1339

Swapping coils without testing is the biggest mistake. Just because coil “C” triggered the code doesn’t guarantee that coil is faulty. A bad ground, damaged wiring harness near the intake manifold, or even moisture inside the coil boot can mimic a failed coil. Another frequent error is ignoring the spark plug condition if the plug in cylinder #3 is worn, fouled, or gapped incorrectly, it can overload the coil and trigger P1339 repeatedly, even after replacing the coil.

How to confirm the real cause

Start simple: inspect the coil-on-plug (COP) unit for cylinder #3. Look for cracks, carbon tracking, or melted plastic. Check the connector for bent pins or corrosion. Then pull the spark plug and examine its condition look for oil fouling, excessive wear, or ash deposits. If both look fine, use a multimeter to test primary resistance (should be ~0.6–1.0 ohms) and secondary resistance (typically 10–15 kΩ). Compare readings to the coil for cylinder #1 or #2 if they differ by more than 15%, the coil is suspect.

For deeper diagnosis, a lab scope helps verify whether the ECU is sending the proper dwell signal to coil “C.” If the signal is present but there’s no spark, the coil is likely bad. If the signal is missing or erratic, the problem may lie in the wiring or ECU driver circuit. You can find step-by-step guidance on interpreting those signals in our P1339 diagnostic trouble code guide.

What else could be mistaken for P1339?

Codes like P0303 (cylinder #3 misfire), P1337 (ignition coil “A” circuit), or even P0353 (ignition coil C primary/secondary circuit OBD2 generic version) can overlap in symptoms but point to different root causes. Don’t assume P1339 means “replace coil C” without verifying. Sometimes a failing crankshaft position sensor or weak battery voltage during cranking can cause intermittent P1339-like behavior. You can compare how P1339 differs from other misfire-related codes in our meaning of code P1339 article.

If you’ve ruled out coil, plug, and wiring and P1339 returns after clearing the issue may involve the ECU’s ignition driver for that channel. That’s less common, but possible. You’ll want to consult a shop with Honda-compatible scan tools if basic checks don’t resolve it. For help narrowing down next steps, see our P1339 code causes engine misfire troubleshooting page.

For reference, Honda’s official service documentation outlines exact resistance specs and test procedures for P1339 diagnostics Honda Service Manual remains the most reliable source.

Next step: Before buying parts, do this quick checklist: • Visually inspect coil C and its connector • Pull and inspect the cylinder #3 spark plug • Test coil resistance with a multimeter • Clear the code and drive see if it returns under the same conditions • If it does, swap coil C with coil A or B and retest; if the code moves to P1337 or P1338, the coil is faulty