What does it mean?
P1357 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Cylinder 1 Ignition Circuit Short to Ground .
Symptoms
- Dead or badly misfiring cylinder 1 with strong vibration at idle
- Check engine light on and flashing during acceleration
- Significant loss of power and hesitation
- Raw fuel smell from the exhaust, with catalytic converter overheating risk
- Rough starting and unstable idle, particularly when the engine is cold
Likely causes
- Control wire chafed through to the cylinder head, a bracket or a metal clip
- Coil with an internally shorted primary winding grounding the control line
- Oil from a leaking valve cover gasket filling the coil well and bridging the terminals
- Harness insulation melted near the exhaust manifold or a turbocharger heat source
- Terminal pushed back and contacting the coil housing or a grounded surface
- Rodent damage or a previous repair that left bare copper touching metal
- Module output driver damaged by the sustained short
How to fix it
- Unplug the cylinder 1 coil and measure resistance from the control wire to ground with the key off; a very low value proves the short
- Inspect the coil well and connector for oil, coolant and water, and clean out any accumulated fluid
- Test the coil primary between its terminals and to the coil body to identify an internal ground fault
- Trace the harness carefully along the head and around brackets, looking for chafe and melted areas
- Repair the damaged section with proper insulation and secure the harness away from heat and sharp edges
- Verify the control line switches correctly with a scope or test light before refitting a new coil
- Replace the coil if it is internally shorted, and inspect the module driver only after the external short is cleared