P0355 — Ignition Coil D Primary/Secondary Circuit Malfunction
Drivable short-term, but fix now to avoid damage.
What P0355 means
This code means the engine computer detected an electrical fault in the primary or secondary circuit of ignition coil D (typically cylinder 4). It most often comes from a failed ignition coil, though damaged wiring or a faulty connector can also set it. It's a common code on coil-on-plug engines and is usually fixed by replacing the affected coil and inspecting its wiring.
Common symptoms
- Check engine light is on or flashing
- Engine misfires or shakes, especially at idle
- Noticeable loss of power or hesitation when accelerating
- Rough or uneven idle
- Increased fuel consumption or a fuel smell
Common causes
- Failed or weak ignition coil on cylinder 4
- Damaged wiring or corroded connector at the coil
- Worn or fouled spark plug on that cylinder
- Loose ground or poor electrical connection
- Failed engine computer driver circuit (less common)
Typical repair cost
$90 – $300
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0355 code?
For short trips, usually yes, but you shouldn't rely on it. A misfiring coil can damage your catalytic converter and leave you with weak power. Get it diagnosed soon and avoid hard acceleration until then.
How much does it cost to fix a P0355 code?
Most repairs run between $90 and $300. A single ignition coil and labor are usually inexpensive, but wiring repairs or replacing a fouled spark plug can add a bit to the total.
Is a P0355 code serious?
It's worth taking seriously. The car may still run, but the misfire it causes can harm the catalytic converter and worsen over time. It's generally an affordable fix when caught early.
What does the 'D' in P0355 refer to?
The 'D' identifies a specific ignition coil, which on most engines corresponds to cylinder 4. The code points the technician straight to that coil's circuit, making the fault easier to locate and repair.