Ignition

P0351 — Ignition Coil A Circuit Malfunction (Cylinder 1)

Severity: medium Drive with care, to a shop

What P0351 means

The ECU monitors the control circuit of ignition coil A, which normally serves cylinder 1. If the coil's signal or response is out of range because of an open, a short or a failing coil, the ECU stores P0351 and turns on the check engine light. P0301, a cylinder 1 misfire, often appears with it.

Symptoms

  • Check engine light on or flashing
  • Rough or unstable idle
  • Misfire on cylinder 1 with engine shaking
  • Loss of power and sluggish acceleration
  • Hard starting
  • Increased fuel consumption
  • P0301 often stored along with it

Possible causes

  1. Failed ignition coil A (internal short or open)
  2. Damaged or corroded wiring or connector at the coil
  3. Worn spark plug overloading the coil
  4. Moisture or dirt in the coil connector
  5. Open or short to ground in the control circuit
  6. Faulty ignition driver inside the ECU (rare)

How to diagnose

  1. Scan all codes and freeze frame data, and look for P0301 or other misfires
  2. Inspect the cylinder 1 coil connector and wiring for moisture, corrosion or burns
  3. Remove the coil and plug, and check the plug condition and the coil for cracks or oil
  4. Swap the coil with one from another cylinder and see whether the fault follows it
  5. Measure coil winding resistance and compare with the manufacturer's spec
  6. Check power, ground and the control signal at the connector with a multimeter or scope
  7. If wiring and coil are good, test the ECU driver

Common fixes

  • Replace ignition coil A
  • Replace the spark plug, ideally the full set
  • Repair the wiring or replace a damaged connector
  • Clean the connector of moisture and corrosion and treat the contacts
  • Repair or replace the ECU if the driver is confirmed faulty

P0351 on different brands

Ford · manuals
On some 2024–2025 engines Ford uses the extended code P0351:11, which flags a short to ground in the coil control circuit; it describes the detected condition, not a specific failed part.

Questions and answers

Can I drive with P0351?

Only briefly and under light load, for example to a shop. Misfires can damage the catalytic converter, and if the check engine light flashes, do not keep driving.

What most often causes P0351?

Most often it is a worn ignition coil on cylinder 1. A corroded connector, damaged wiring or an old spark plug can also cause it.

How do I tell if the coil is the problem?

Swap the cylinder 1 coil with a neighboring one and clear the codes. If the misfire and code move to the other cylinder, the coil is bad.

This is general information about the code. The meaning can differ between makes and models: a scan tool and the repair manual for your car will show the exact cause.