What does it mean?
P1227 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 3 Fuel Injection Circuit Short to Ground .
Symptoms
- Check engine lamp on with a cylinder 3 misfire counted
- Very rough idle and a shudder felt through the pedals
- Rich running, black smoke and unburnt fuel smell at the tailpipe
- Spark plug on that cylinder wet with fuel and quickly fouled
- Difficult starting, in some cases no start when the fuse has blown
Likely causes
- Chafed control wire touching the engine, a metal clip or a heat shield
- Injector connector filled with coolant or washing water
- Injector coil shorted to the injector case
- Loom trapped when the engine cover or wiring channel was refitted
- Corroded terminal that has partly melted and contacts the connector shell
- Module driver damaged, which can blow the shared injector fuse
How to fix it
- Look for a blown injector fuse and check which cylinders lost their supply with it
- With the injector unplugged, measure control wire to ground resistance; a low value confirms the short
- Trace the injector branch of the loom and inspect every point where it touches metal
- Dry and inspect the connector, then measure from each injector pin to the injector body
- Compare injector resistances across the engine to isolate an internally shorted unit
- Repair the damaged wiring, protect it with a sleeve and retest the circuit
- Replace the injector if it is shorted internally, and only then evaluate the module driver