If your check engine light is on and a scan tool shows P1339, you’re likely dealing with a cylinder 3 misfire that the car’s computer has confirmed not just suspected. This isn’t a vague warning or a sensor glitch in most cases. It means the engine control module (ECM) detected a real loss of power from cylinder 3, usually because fuel isn’t burning properly there. That affects drivability, fuel economy, and emissions and if ignored, it can damage the catalytic converter.

What does P1339 actually mean?

P1339 is a manufacturer-specific OBD-II code used by Volkswagen, Audi, Seat, and Skoda vehicles. It stands for “Cylinder 3 Misfire Detected.” Unlike generic codes like P0303 (which also points to cylinder 3), P1339 often implies the misfire was confirmed over multiple engine cycles and may involve additional criteria like crankshaft position variance or combustion pressure inconsistency. It’s not just “a spark plug issue.” It’s the ECM saying, “I’ve watched this happen repeatedly, and cylinder 3 isn’t contributing as it should.” You’ll find more detail in our meaning of code P1339 page, which breaks down how VW’s logic differs from generic misfire detection.

When do people see P1339 and what symptoms go with it?

You’ll typically get P1339 when the car stumbles under load like accelerating from a stop, climbing a hill, or passing at highway speed. Common signs include:

A rough idle that’s worse when the engine is warm
Noticeable hesitation or jerking from the drivetrain
Loss of power specifically between 2,000–4,000 RPM
Occasional backfiring through the intake or exhaust
Increased fuel consumption without other obvious causes

It’s rare to see P1339 without noticeable drivability issues. If the car feels fine but the code appears, double-check for intermittent wiring faults or a recent battery disconnect that reset adaptive values.

What causes P1339 and what do people get wrong?

The most common cause is a failing coil-on-plug (COP) unit for cylinder 3 but not always. People often replace just the coil and call it done, only to have the code return days later. That’s because P1339 can also stem from:

A clogged or leaking fuel injector specific to cylinder 3
Low compression due to worn valves, carbon buildup, or a leaking head gasket
Vacuum leaks near the intake runner for cylinder 3
Ignition timing errors caused by a stretched timing chain or faulty camshaft position sensor

We cover these root causes in depth in our P1339 code causes guide, including which tests to run before swapping parts.

How to diagnose P1339 without guessing

Start simple: inspect the COP boot and connector for cylinder 3. Look for cracks, carbon tracking, moisture, or corrosion. Swap that coil with cylinder 1’s (if the engine layout allows easy access), then clear the code and drive. If P1339 moves to cylinder 1, the coil is faulty. If it stays on cylinder 3, the problem is elsewhere like the injector or mechanical condition.

Don’t skip a compression or leak-down test if the misfire persists after confirming ignition and fuel delivery. A weak valve spring or burnt valve won’t trigger a generic code but will reliably set P1339 under load. Our engine misfire diagnosis walkthrough walks through each test step-by-step, with torque specs and expected readings for common VW/Audi engines like the 1.8T, 2.0T FSI, and EA888.

Real next step: What to do right now

Before buying parts or booking a shop visit:

Write down all symptoms including when they happen (cold start? only under load?)
Check for oil in the spark plug well for cylinder 3 (a sign of valve cover gasket leak affecting spark)
Look for vacuum hoses near the intake manifold that are cracked or disconnected especially those feeding cylinder 3’s runner
Clear the code and drive normally for two full drive cycles (start → warm up → highway load → cool down)
If P1339 returns, pull the spark plug for cylinder 3 and inspect for fouling, gap erosion, or wetness

If you’re comfortable with basic diagnostics, that list will narrow things down fast. If not, bring those notes and the live data from your scan tool to a technician who works regularly on VW/Audi platforms. They’ll know where to look first.

Engine Misfire Code P1339 Explanation