P0354 means Ignition Coil D Primary/Secondary Circuit. The computer has detected a fault in the circuit for ignition coil D, the coil it drives on its D output. On many engines coil D fires cylinder 4, but the coil-to-cylinder assignment varies by engine. It is a generic OBD-II code, so the definition is the same on any make, but the most likely cause varies by engine; confirm with a scan tool and the service information for your vehicle before buying parts.
What P0354 means
Most modern engines use coil-on-plug ignition, with one coil per cylinder (or per pair of cylinders) switched by a driver inside the engine computer. The computer monitors each coil circuit, and a fault there usually comes with a misfire on the matching cylinder, so coil and misfire codes are diagnosed together.
P0354 symptoms
- Misfire on the affected cylinder
- Rough idle and shaking
- Check engine light, often flashing under load
Common causes of P0354
- Failed ignition coil
- Damaged connector or wiring to the coil
- Open or shorted driver circuit in the engine computer (less common)
How to diagnose P0354
- Read misfire counts to confirm which cylinder is affected
- Swap the coil with a neighboring cylinder and see whether the code or misfire follows it
- Check the coil connector and its wiring for damage and corrosion
- Check power and the driver signal at the coil
Can you drive with P0354?
Only briefly and gently: a dead cylinder can overheat the catalytic converter.
P0354 tips
On coil-on-plug engines, a cracked boot or carbon-tracked spark plug can damage a new coil; replace the plug and boot when replacing the coil.
Will P0354 clear itself?
If the fault stops, the computer turns off the check engine light by itself after several drive cycles without seeing it again, and the code stays in memory as history for a while. Clearing P0354 with a scan tool after a repair is fine, but if the cause is still there the code returns, sometimes within one drive. Disconnecting the battery also clears codes on most vehicles, but it erases learned fuel trims and idle settings as well.
Related codes
| Code | Meaning |
|---|---|
| P0304 | Cylinder 4 Misfire Detected |
| P0300 | Random/Multiple Cylinder Misfire Detected |
| P0351 | Ignition Coil A Primary/Secondary Circuit Malfunction |
Guides that help
When it is more than a sensor
If a coil and plug swap does not move the misfire and a compression or leak-down test shows a burnt valve or failed head gasket, the decision becomes repair versus replacement; see engine replacement cost and compare engines by code on our engines page.
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