OBD-II · Engine and powertrain (P)
P0351
Ignition coil A primary control circuit/open
What it means
The ECU detects an electrical fault in the control circuit of ignition coil A (usually the coil for cylinder 1).
Symptoms
- misfire and rough running
- loss of power
- engine warning light, possibly flashing
Likely causes, most likely first
| No. | Cause |
|---|---|
| 01 | failed ignition coil |
| 02 | damaged coil connector |
| 03 | wiring open or short |
| 04 | worn spark plug overloading the coil |
| 05 | ECU driver fault |
What to check, step by step
- 01Check for a matching misfire code (usually P0301)
- 02Inspect the coil connector and wiring for damage, corrosion or oil
- 03Swap the coil with a neighbouring cylinder, clear codes and see whether the fault follows the coil
- 04Check the coil power supply and ground, and the ECU trigger signal with a scope if needed
- 05Replace the coil, and the spark plugs if they are worn