What it means
The control module detected restricted fuel flow through the cylinder 9 injector.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The fuel injector meters fuel into cylinder 9 when the engine control module commands it to open. The module detects restricted fuel delivery through this injector, which can leave cylinder 9 short of fuel even if other cylinders operate normally.
Common causes
Most likely first.
- Clogged or restricted cylinder 9 injector
- Contaminated fuel or deposits in the injector
- Low fuel pressure or restricted fuel supply
- Injector wiring or driver fault
Symptoms
- Check-engine light on
- Rough idle or cylinder 9 misfire
- Reduced power or hesitation
- Poor fuel economy
How to diagnose it
- Record freeze-frame data and compare cylinder 9 misfire or contribution data with the other cylinders to see when the restriction appears.
- Inspect the cylinder 9 injector connector and wiring for loose pins, corrosion, damage, or chafing.
- Check fuel quality and inspect the supply to the cylinder 9 injector for a blockage or other restriction.
- Use available scan-tool tests to compare cylinder 9 injector operation with the other cylinders.
- Test the cylinder 9 injector electrical circuit and driver control against the manufacturer's specification.
- If the circuit and supply are sound, test cylinder 9 injector flow using the vehicle maker’s approved procedure.
Common fixes
- Repair a loose, corroded, or damaged cylinder 9 injector connector or wiring.
- Correct a restriction in the fuel supply to the cylinder 9 injector.
- Address contaminated fuel and replace the fuel filter if inspection or the service schedule indicates it is needed.
- Clean or replace the restricted cylinder 9 injector after confirming the fault.
Can I keep driving?
A short, gentle drive may be possible if the engine runs smoothly, but avoid hard acceleration and long trips. A persistent cylinder 9 misfire can damage the catalytic converter, so stop driving if the engine runs very rough or the check-engine light flashes.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.