Workshop · diagnostics and repairsWe reply the same day
Diagno.ee
Ignition and misfires

P0309 Misfire in cylinder 9

By: · Updated:

P0309 means: Misfire in cylinder 9. Fuel isn't burning properly in a cylinder. Don't drive until the car has been checked. The engine could be damaged. The most common repair costs about €60–120 in Estonia, depending on make and model. The most common cause: worn spark plugs.

Is it safe to drive?Don't driveDon't drive until the car has been checked. The engine could be damaged.
Spark plug replacement€60–120parts and labour in Estonia, depending on make and model

What it means

Fuel isn't burning properly in a cylinder. The engine runs unevenly and unburnt fuel can damage the catalytic converter. A number at the end shows the cylinder.

What you may notice

  • The engine jerks and shakes
  • Engine light flashing or on
  • Less power
  • Higher fuel consumption

What could be wrong

  1. 1Worn spark plugs · Spark plug replacement €60–120
  2. 2Faulty ignition coil · Ignition coil replacement €90–180
  3. 3Clogged or leaking injector · Injector replacement €200–400
  4. 4Air leak · Leak check and hose or gasket replacement €60–120
  5. 5Low cylinder compression · Engine mechanical repair (after compression test) €600–1200

Repair difficulty: Moderate

What you can check yourself

If the engine light is flashing, drive gently to the nearest safe stop. Swap the coils between cylinders and see whether the fault moves. You can check the simple things yourself, but the repair is best done in a workshop.

How we fix it

  1. We check spark plugs and coils
  2. We check injectors and air leaks
  3. If needed we test compression
  4. We replace the plugs, coil or injector

Standard SAE description: Cylinder 9 Misfire Detected

This code usually comes with: Check engine lightSee what the light means →

Related symptoms: Car shaking or jerking

Want a definite answer?

Bring the car to our workshop in Estonia for diagnostics. We read the fault codes, test the sensors and tell you what is wrong. Repair price depends on the work involved, generally €45 per hour.

Book a diagnostic check

Questions

What does fault code P0309 mean?

Misfire in cylinder 9. Fuel isn't burning properly in a cylinder. The engine runs unevenly and unburnt fuel can damage the catalytic converter. A number at the end shows the cylinder.

Can I drive with code P0309?

Don't drive until the car has been checked. The engine could be damaged.

How much does it cost to fix P0309?

It depends on the cause: spark plug replacement €60–120; ignition coil replacement €90–180; injector replacement €200–400. Prices include labour at €45/h, depending on make and model.

How is P0309 fixed?

We check spark plugs and coils. We check injectors and air leaks. If needed we test compression. We replace the plugs, coil or injector.

Related codes

P0308Misfire in cylinder 8P0307Misfire in cylinder 7P2321Ignition coil control circuit: signal or voltage too low ("H")P2322Ignition coil control circuit: signal or voltage too high ("H")P2323Ignition coil secondary circuit: circuit fault ("H")P0420Catalytic converter no longer cleaning properlyP0008Crank/cam sync: reading or operation not right (bank 1)

Based on AI combined with our hands-on workshop experience and knowledge. This information is general and prices are approximate (Estonian workshop rates). The same code can mean different things on different cars. Only an inspection of the car gives a definite answer.

Book a diagnostic check