Faulty ignition coil D with an open primary winding; Damaged, corroded or loose coil connector terminals; Open circuit, chafing or high resistance in the wiring between the coil and the control unit; Missing or faulty power supply or earth to the coil or its driver; Blown fuse or faulty relay feeding the ignition coil circuit; Fault in the control unit's ignition driver.

P0354

Ignition Coil D Primary Control Circuit/Open.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
3: AreaIgnition system or misfire
54: FaultThe specific fault in that area

What it means

P0354 means the engine control unit has detected an open circuit in the primary control circuit for ignition coil D, which is normally the coil serving cylinder 4 on a multi-coil engine. The control unit monitors the coil driver or the signal it sends to the coil, and sets the code when the expected electrical response is missing. The result is usually a misfire on the affected cylinder, though the exact coil layout depends on the engine.

Symptoms

Engine management light on, possibly flashing under load if a misfire is severe
Rough idle and noticeable engine shaking
Hesitation or loss of power when accelerating
Misfire codes stored alongside P0354, often P0304
Poor fuel economy
Hard starting or the engine running on fewer cylinders

Possible causes

Faulty ignition coil D with an open primary windinglikely
Damaged, corroded or loose coil connector terminalslikely
Open circuit, chafing or high resistance in the wiring between the coil and the control unitlikely
Missing or faulty power supply or earth to the coil or its driverpossible
Blown fuse or faulty relay feeding the ignition coil circuitpossible
Fault in the control unit's ignition driverrare

How to diagnose

Read all stored codes and freeze frame data to see engine load, speed and temperature when the fault set, and check for misfire codes on the cylinder served by coil D
Confirm which cylinder coil D serves for this engine using the manufacturer's data, as the layout varies by model
Inspect the coil connector and wiring for damage, corrosion, water ingress, chafing or pushed-out terminals
Swap coil D with a coil from another cylinder, clear the codes and see whether the fault or misfire follows the coil
Check the coil's power supply, earth and related fuses or relays with a multimeter against the wiring diagram
Test the control signal circuit for continuity and short to earth or supply between the coil connector and the control unit
Check the coil primary resistance against the specification for that engine
Only if wiring and coil are proven good, have the control unit's driver output checked

How to fix

Replace the faulty ignition coil D, and inspect the spark plug in that cylinder at the same time
Repair or replace damaged wiring, and clean or renew corroded or loose connector terminals
Restore the power or earth supply to the coil, including replacing a blown fuse once the cause of the failure is found
Replace a faulty relay in the ignition supply circuit
Repair or replace the control unit only after all other causes are ruled out

Can I keep driving?

Medium severity

The car can be driven a short distance if it runs reasonably, but fix it soon. Continued misfiring can overheat and damage the catalytic converter, so avoid heavy loads, and stop driving if the warning light flashes.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.