What it means
The control module detects a high condition in the cylinder 9 injector circuit. This indicates an electrical circuit fault and does not by itself establish an injector flow problem.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The cylinder 9 injector circuit carries the control module’s command to meter fuel into cylinder 9. The module monitors the circuit’s electrical response and sets this code when it detects a high condition, which can result from a short to battery voltage and does not by itself prove an injector flow fault.
Common causes
Most likely first.
- Wiring shorted to battery
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check-engine light
- Rough idle or misfire
- Reduced power
- Increased fuel consumption
How to diagnose it
- Save the freeze-frame data and check live data for cylinder 9 misfire or injector circuit indications to identify the conditions when the high reading occurs.
- With the engine off, inspect the cylinder 9 injector connector and harness for corrosion, loose or backed-out pins, damaged insulation, or a supply wire pinched against a B+ source.
- Using the manufacturer's wiring diagram, check whether the cylinder 9 injector control wire is shorted to battery voltage.
- Test the circuit and connector continuity and isolation from power sources according to the manufacturer's procedure.
- If the wiring passes, test the cylinder 9 injector and control-module driver using the manufacturer's procedure before considering module replacement.
Common fixes
- Repair or reroute cylinder 9 injector wiring that is pinched against a battery supply.
- Clean or replace corroded cylinder 9 injector connector terminals and secure any backed-out pins.
- Repair damaged insulation or a section of wire shorted to battery voltage.
- Replace the cylinder 9 injector if its electrical fault is confirmed by testing.
Can I keep driving?
If the engine runs smoothly and the warning light is steady, drive only as needed for prompt diagnosis; a cylinder 9 circuit fault can cause a misfire, reduced power, and excess emissions. Avoid heavy acceleration, and stop if the light flashes or the engine begins running very roughly.
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.