Ignition Coil D Primary/Secondary Circuit
The ignition monitor detected a primary or secondary circuit problem associated with coil D. This applies to spark-ignition engines and does not prove the coil itself failed. Letter D is a manufacturer-defined circuit designation, not a universal promise that it serves cylinder 4. Identify the correct coil from service information and test its supply, wiring and control before replacing components.
Can I keep driving?
If the engine stalls, the light flashes, shaking is severe, or power loss makes traffic unsafe, pull over safely and arrange towing. With a steady light and normal operation, ask a shop for advice based on symptoms before further driving.
Flashing light, burning smell or smoke? Pull over safely. Danger to life: call 911.
What does this code mean for your car?
The same code can need different checks depending on the model and engine. Enter your vehicle details to find relevant sources and checks.
Symptoms
- Shaking or misfiring
- Hesitation or reduced power
- Engine warning that may flash
Possible causes
- 1Internal coil D fault
- 2Open or short in supply or control wiring
- 3Damaged connector or poor terminal contact
- 4Ignition driver or controller fault
These possibilities are not ranked by frequency and do not diagnose your vehicle.
Checks you can safely do yourself
Safe checks only: engine off and cold, car on level ground.
- Save the code and freeze-frame data if your scanner offers them, without clearing anything.
- Check how engine service information identifies coil D; do not pull coils, ignition leads or connectors, or attempt a spark test.
When you need a shop
A flashing light or severe shaking calls for stopping and towing. The shop should verify coil D mapping, test wiring, supply and control signals, and assess accompanying misfire codes before replacing the coil.
How much does it cost?
A US repair estimate needs a diagnosis and a local shop quote.
No verified US repair quote is available for this fault. The price depends on diagnosis, vehicle, parts and local labor; request 2-3 itemized quotes.
Get 2-3 quotes
Investigate this code for my carFAQ
Can I keep driving with P0354?
If the engine stalls, the light flashes, shaking is severe, or power loss makes traffic unsafe, pull over safely and arrange towing. With a steady light and normal operation, ask a shop for advice based on symptoms before further driving.
What can cause P0354?
Possible causes include internal coil D fault; open or short in supply or control wiring; damaged connector or poor terminal contact; ignition driver or controller fault. These are diagnostic possibilities, not a confirmed diagnosis or a parts shopping list.
Does clearing the code fix the problem?
No. Clearing a code does not repair the problem or prove that no fault exists. It may erase useful evidence and reset readiness monitors. Save codes and freeze-frame data first; confirming a repair requires the vehicle-specific checks.
What if this code appears during a used-car inspection?
Arrange an independent professional pre-purchase inspection before committing. Request a complete scan, readiness status and diagnosis of the relevant system. Get written findings and a repair estimate; an unlit warning lamp does not replace inspection.
How much does a P0354 repair cost?
No verified US repair quote is available for this fault. The price depends on diagnosis, vehicle, parts and local labor; request 2-3 itemized quotes.