P0351: Ignition coil "A" primary/secondary circuit malfunction
The engine computer has found a fault in the circuit it uses to switch an ignition coil. Without a spark, the cylinder that coil serves misfires.
Updated
What P0351 means
On most modern petrol engines each cylinder has its own ignition coil, which the engine computer switches on and off to make the spark. The computer watches the circuit it uses to switch each coil.
P0351 means it found a fault in the circuit of coil “A”. That doesn’t always mean a misfire has happened yet, but a coil that doesn’t get a proper signal can’t make a spark.
P0352 to P0362: coils B to L
Each code names one coil by letter, from B (P0352) to L (P0362). Which cylinder each coil serves depends on the engine; the service information for your car shows it, and a misfire code stored at the same time also points to the cylinder. The meaning, causes and advice are the same for each.
P0352: Ignition coil "B" primary/secondary circuit malfunction
P0353: Ignition coil "C" primary/secondary circuit malfunction
P0354: Ignition coil "D" primary/secondary circuit malfunction
P0355: Ignition Coil E Primary Control Circuit/Open
P0356: Ignition Coil F Primary Control Circuit/Open
P0357: Ignition Coil G Primary Control Circuit/Open
P0358: Ignition Coil H Primary Control Circuit/Open
P0359: Ignition Coil I Primary Control Circuit/Open
P0360: Ignition Coil J Primary Control Circuit/Open
P0361: Ignition Coil K Primary Control Circuit/Open
P0362: Ignition Coil L Primary Control Circuit/Open
Can I keep driving?
Drive gently
Avoid hard driving and have it checked soon. It can damage the engine or catalytic converter. If the check engine light flashes, stop when it’s safe to do so.
General guidance based on the code alone, not on the car’s actual condition. If in doubt, stop and ask a mechanic.
A cylinder without a spark lets unburnt fuel into the exhaust, where it can overheat the catalytic converter. If the check engine light flashes, stop when it’s safe to do so.
Symptoms
- The engine shakes or runs unevenly, often with a misfire code (P0300 to P0312) for the same cylinder.
- Less power or hesitation when accelerating.
- Hard starting, on some cars.
- A check engine light that flashes while the misfire is severe.
Common causes
- Faulty ignition coil. Coils can fail with heat and age, sometimes only when warm. Where the engine allows, swapping it with a neighbouring coil shows whether the fault moves with it.
- Wiring or connector fault at the coil. Look for a loose plug, a broken wire or corrosion.
- Blown fuse or fault in the coils’ power supply. If several coil codes appear at once, a shared fuse or power feed is more likely than several faulty coils.
- Fault in the coil driver inside the engine computer. Less common. On some cars a faulty coil can damage the driver, so replace the coil before suspecting the computer.
Typical fixes
- Note which coil codes and misfire codes are stored.
- Check the coil’s plug and wiring for damage and corrosion, and the fuse for the coils.
- Swap the coil with a neighbouring one, where the engine allows, and see whether the fault follows it.
- Have the coil’s power supply and control signal checked if the coil and wiring are fine.
- Clear the codes after the repair and check that the engine runs evenly.
Questions
Can I drive with P0351?
Gently, and not far. The app’s advice is to avoid hard driving and have it checked soon, because a cylinder without a spark can damage the catalytic converter. If the check engine light flashes, stop when it’s safe to do so.
Which cylinder is coil A?
The code names the coil by letter, not by cylinder, and which cylinder each coil serves depends on the engine. Check the service information for your car. A misfire code stored with it (P0301 to P0312) also names the cylinder.
Is P0351 the same as a misfire code?
No. P0351 is about the coil’s circuit; a misfire code means the computer saw a cylinder misfire. They often come together, because a coil that fails makes its cylinder misfire.