P0357Ignition Coil "G" Primary/Secondary Circuit
What it means
The ECU sees a fault in the control circuit of ignition coil "G" (usually the coil for cylinder 7). The coil may not fire at all, so that cylinder misfires.
Symptoms
- Misfire on cylinder 7
- Rough running and loss of power
- Check engine light, sometimes flashing
Common causes
- Failed ignition coil (open or shorted winding)
- Open or shorted coil control wire
- Missing coil supply (fuse, relay) or ground
- ECU coil driver fault
What to check first
- Check the coil supply and ground with the key on
- Scope the coil control signal while cranking
- Swap the coil with another cylinder and see whether the fault follows
Generic OBD-II meaning. Manufacturer-specific meanings and checks can differ; always check the service information for the car.