P0350 Ignition Coil Primary/Secondary Circuit Malfunction

P0350 indicates a general ignition coil primary or secondary circuit malfunction. The controller has detected a problem in coil control, coil feedback, or the high-voltage ignition path.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace all coils for P0350 until shared power, ground, control, and secondary ignition problems have been separated.

Symptoms of P0350

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0350

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Check misfire counters, coil command, primary voltage, ignition feed, grounds, fuse status, and whether the fault affects one coil or the shared coil supply.
Inspect coil connectors, harness routing, driver circuits, spark plug condition, secondary leakage, moisture intrusion, and signs of arcing.
Use swap testing only when the coil layout allows it and confirm whether the code follows the coil, wiring, plug, or cylinder.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.