obd2.help

P0351

Ignition Coil A Primary/Secondary Circuit Malfunction

The engine computer is seeing a problem in the ignition coil circuit for cylinder 1. This can stop that cylinder from firing correctly and can cause rough running, misfires, and poor fuel economy.

Severity4/5 High
Can I drive?⚠ With caution

You may be able to drive short distances, but the engine can run rough and may lose power. Continued driving can damage the catalytic converter and worsen the problem.

DIY
$20–$150
Shop
$120–$450
Difficulty
intermediate

What It Means

P0351 sets when the PCM detects an electrical fault in the ignition coil A circuit, usually the coil serving cylinder 1 on many vehicles. The fault may be on the coil primary control side, the secondary output side, or the wiring/connectors between the PCM and the coil. The code often appears with a misfire code if the coil is not firing correctly.

Symptoms

Common Causes

1. Bad ignition coilhigh
2. Damaged, loose, or corroded coil connector or wiringhigh
3. Failed spark plug causing excessive coil load or misfiremedium
4. PCM driver circuit problemmedium
5. Water, oil, or corrosion intrusion into the coil well or connectormedium
6. Blown fuse or power supply issue to the ignition coillow
7. Harness short to power or groundlow

Related Codes

FAQ

What does P0351 usually mean?

It usually means the ignition coil circuit for cylinder 1 has an electrical fault or the coil is not firing correctly.

Can a bad spark plug cause P0351?

Yes. A worn or fouled spark plug can overload the coil or cause misfire symptoms that lead to this code.

Will replacing the coil always fix P0351?

No. Wiring, connectors, spark plugs, and the PCM control circuit can also cause this code.

Is P0351 serious?

Yes. It can cause misfires, power loss, and catalytic converter damage if driven too long.