P0354: Ignition Coil D Primary/Secondary Circuit Malfunction

What does the P0354 error code mean?

P0354 is a diagnostic trouble code that translates to "Ignition Coil D Primary/Secondary Circuit Malfunction." This code indicates an issue with one of the engine's ignition coils; the "D" generally means the issue is associated with the engine's No. 4 cylinder. Modern engines feature an ignition coil for each cylinder that is used to fire that cylinder's spark plug. If the vehicle's powertrain control module sees incorrect feedback from either the primary or secondary portion of the ignition coil, this trouble code will result.

Why is this issue important?

Each cylinder relies on the properly timed firing of a spark plug to transform the energy in fuel into motion. When there's a problem with the ignition coil, it can prevent the spark plug from firing, which means that the cylinder won't contribute to the engine's power. This, in turn, can result in unburned fuel being wasted and the engine making less power than it's designed to while also running roughly.

Can I safely drive my car with this error code?

It's best to avoid driving a vehicle with this trouble code. The vehicle likely won't be producing its full power, and continued operation when down a cylinder can cause an imbalance that may lead to other problems. It's best to take the vehicle to get checked out as soon as you detect the P0354 error code.

Common symptoms of the P0354 error code

• The check engine light is illuminated.
• The engine idles and runs roughly, and it may misfire.
• The engine is down on power and is less responsive.
• The engine may have trouble starting.

How is the P0354 error code diagnosed?

• Use an OBD-II scanner: Confirm the presence of the P0354 code and check for any related error codes before proceeding. It's possible that the P0354 error is being caused by another system problem.
• Feel and listen for misfires: Noting rough engine running helps verify that the error code is accurate.
• Visually inspect the coil: Check for any frayed wires leading to or from the ignition coil and any corroded or melted parts in or around it.
• Visually inspect the spark plug: Remove the spark plug and note any corrosion or other issues with it.
• Check the ignition coil: Use a multimeter to measure its resistance, the voltage entering the coil, and the voltage returning from the coil to the spark plug.
• Test the powertrain control module: If no external issues are found, the powertrain control module itself may be faulty and require further testing, a reset or replacement.

How is the P0354 error code repaired?

• Replace a faulty ignition coil.
• Replace damaged wiring in the ignition system.
• Replace one or more spark plugs.
• Reset or replace the powertrain control module.

Related reading

Follow the link below to reach our diagnostic check engine trouble codes catalog:
On-board diagnostics (OBD-II) trouble code directory