P0354 Code: Ignition Coil D Primary/Secondary Circuit Malfunction
🟠 Moderate severity · drivable
Drivable short-term, but cylinder 4 will misfire and raw fuel can damage the catalytic converter. Stop if the light flashes.
What P0354 means
There's an electrical fault in the ignition coil circuit for cylinder 4 (coil D). The computer can't command that coil to fire, so cylinder 4 loses spark and misfires — P0354 often appears alongside a P0304 cylinder 4 misfire for exactly this reason.
Symptoms
- Check engine light on (may flash)
- Misfire or rough idle on cylinder 4
- Loss of power
- Poor fuel economy
Common causes
- most common: Faulty ignition coil on cylinder 4 (coil D)
- common: Damaged wiring or a loose connector at the coil
- less common: Ignition driver failure inside the engine computer (PCM)
How to fix it
| Fix | DIY? | Typical cost |
|---|---|---|
| Swap the cylinder 4 coil with another cylinder to see if the misfire follows it | Yes | $0–20 |
| Replace the cylinder 4 ignition coil | Yes | $50–200 |
| Repair damaged coil wiring or connector | Mechanic | $50–150 |
Frequently asked questions
Which cylinder is coil D?
Coil D fires cylinder 4. P0354 is the cylinder 4 coil circuit.
How do I confirm a bad coil on P0354?
Swap the cylinder 4 coil with another cylinder and re-scan. If the misfire moves, the coil is bad.
Does P0354 cause a misfire?
Yes — without spark on cylinder 4, you get a misfire, so P0354 and P0304 often occur together.
Related codes
P0304
P0304 Code: Cylinder 4 Misfire Detected
P0350P0350 Code: Ignition Coil Primary/Secondary Circuit Malfunction
P0353P0353 Code: Ignition Coil C Primary/Secondary Circuit Malfunction
Related guide: The 10 Most Common Check Engine Codes →
Updated 2026-08. This page is informational and not a substitute for professional diagnosis.