Cylinder 9 Misfire Detected
What it means
This code only appears on engines with nine or more cylinders, such as V10 and V12 engines. It means the engine computer has seen cylinder 9 repeatedly fail to fire, usually because of the ignition parts or injector serving it.
Symptoms4
- Mild shaking at idle that may not be obvious.
- Slight loss of power.
- Check engine light on, possibly flashing.
- Higher fuel consumption.
Possible causes6
- Worn spark plug in cylinder 9.
- Weak ignition coil for cylinder 9 or a cracked boot.
- Clogged or faulty cylinder 9 injector.
- Damaged wiring or connector for this cylinder.
- Vacuum leak near its intake runner.
- Low compression in the cylinder (less common).
How to diagnose5
- Confirm the engine has nine or more cylinders and locate cylinder 9 in the service manual.
- Watch the misfire counter for this cylinder and the rest of its bank.
- Inspect the plug, then swap the coil with another cylinder and see whether the misfire moves.
- Check the injector and its signal.
- Have a compression test done if the fault remains.
How to fix6
- Replace the spark plug, or the full set if it is due.
- Replace the faulty ignition coil.
- Repair the wiring or connector.
- Clean or replace the injector.
- Fix a vacuum leak or low compression if confirmed.
- Clear the codes, drive and confirm the code does not return.
Repair cost
In Saudi riyals; the highlighted part is the expected range for this fault.
Parts for these large engines cost more and labor to reach the plugs and coils is higher, so the top of the range is above that of smaller engines.
Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026
Frequently asked questions
My engine has eight cylinders and shows this code. Why?
The code is meant for engines with nine or more cylinders. If it appears on a smaller engine, re-read it with a reliable scan tool and have a shop check it, because this is unusual.
Is the repair different from other cylinders?
The steps are the same: check the plug, swap the coil, then check the injector and compression. Reaching the parts may simply take longer on these engines.
This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.
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