CarSense › Trouble codes › P0351

P0351: Ignition Coil A Primary/Secondary Circuit Malfunction

What this check-engine code means in plain English, what usually causes it, and what a fix typically costs.

Severity: Urgent — can cause engine damage if driven with active misfires

What P0351 means

The powertrain control module (PCM) has detected a malfunction in the primary or secondary circuit of ignition coil A (cylinder 1). This means the coil is not receiving proper voltage, has an internal failure, or the circuit has a wiring problem, preventing proper spark delivery to cylinder 1.

What causes P0351?

Likely
Failed ignition coilThe ignition coil itself has failed internally and cannot generate the high voltage needed for spark.
Likely
Damaged wiring or connectorCorroded, loose, or broken wiring between the PCM and ignition coil disrupts the electrical signal.
Possible
Faulty spark plug or wireA worn spark plug or damaged plug wire can cause excessive resistance and trigger coil circuit codes.
Less common
PCM failureThe engine computer itself may have a failed ignition coil driver circuit, though this is rare.

Is P0351 safe to drive?

Drive it?
Not recommended
Watch for
Rough idle, misfires, loss of power, or engine damage
DIY-friendly?
Moderate — coil replacement is straightforward, but diagnosis requires basic electrical testing.

Driving with this code is not recommended. A malfunctioning ignition coil typically causes cylinder 1 to misfire, which can damage the catalytic converter due to unburned fuel, cause rough running, and lead to poor fuel economy. Prolonged driving with misfires risks expensive catalytic converter failure.

P0351 repair cost

~$150 – $400+

Industry-average estimates. Cost depends on whether only the ignition coil needs replacement or if wiring repair or spark plugs are also required.

Which one is it for your car?

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