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  • The P0354 code stands for “Ignition Coil ‘D’ Circuit Malfunction,” which means the powertrain control module (PCM) has detected an issue with the primary or secondary circuit for ignition coil “D.”
  • Some of the possible causes of the P0354 code are a bad ignition coil, an issue with the ignition coil circuit, and a faulty PCM.
  • An illuminated Check Engine Light, rough idling, and engine misfires are some of the common symptoms of the P0354 code.

The powertrain control system (PCM) manages the ignition coils that ignite the spark plugs at precisely the right time. If the PCM detects a potential problem with the ignition coil “D” (which is the cylinder #4 ignition coil) or its circuit, code P0354 may be set.

What Does the P0354 Code Mean?

Diagnostic trouble code (DTC) P0354 stands for “Ignition Coil ‘D’ Circuit Malfunction.” It indicates that the PCM has detected a problem either in the primary or secondary circuit for ignition coil “D”. Typically, when a cylinder is referenced using letters of the alphabet this way, “A” is cylinder 1, “B” is cylinder 2, and so on.

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There are several types of ignition systems, including a distributor, coil pack, or coil on plug (COP) type systems. Typically, code P0354 is set in a COP system.

coil pack design ignition coil
There are several types of ignition systems, including a distributor, coil pack, or coil on plug (COP) type systems.

In an engine with a COP ignition system, each cylinder comes with its own ignition coil that sits on top of the spark plug. The computer monitors the circuit between it and every ignition coil for faults. It will file a trouble code depending on the cylinder that experienced a fault in its circuit. For example, code P0354 indicates a problem with ignition coil “D”, which is the coil on cylinder #4, or its circuit.

Every ignition coil has a “primary” winding and a “secondary” winding. The primary winding is the part of the ignition coil that is triggered by a switching device so that the secondary winding creates the necessary high voltage spark. Since the ECM/PCM is triggering the primary of each coil or each pair of coils, it has the ability to watch the voltage spike created by the primary winding each time it triggers the secondary winding, and if the ECM/PCM doesn’t see the primary voltage spike that indicates the coil fired, it knows there is a problem of some kind with the primary and possibly the secondary elements of the coil or coil pack. If the secondary part of the ignition coil is shorted out, the primary spike will be weak as a result. That’s when it typically sets the P0354 code if the fault is on cylinder #4.

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For more information about the parts of an ignition coil, you can read our technical discussion about the primary and secondary windings of ignition coils.

You may also watch this video to understand how ignition coil works:

Continue reading to learn the possible causes of code p0354.

Note: The Society of Automotive Engineers (SAE) laid down the details about the generic code P0354. The code’s definition may change according to the vehicle’s manufacturer.

What are the Possible Causes of the P0354 Code?

Common symptoms associated with the P0354 code, include:

  • Bad or failing ignition coil
  • An issue with the ignition coil circuit
  • Faulty PCM or PCM software in need of an update

What are the Common Symptoms of the P0354 Code?

Some warning signs of a code P0354 include:

Some car manufacturers programmed the PCM of several vehicle models to shut down the fuel injector of a cylinder when code P0354 is set.

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coil on plug ignition coil
Typically, code P0354 is set in a COP system.

How to Diagnose the P0354 Code

Once the scanner shows the P0354 code logged by the PCM, most car owners bring their vehicle to the nearest auto repair shop. If you have plenty of DIY car repair experience under your belt, you can try to diagnose the issue and fix the P0354 Ignition Coil D Location malfunction.

Watching the video below can give you an idea of what the troubleshooting process might involve:

How to Fix the P0354 Code

Once you’ve determined what triggered the issue, figure out how to resolve it. Use online auto repair resources and guides. However, keep in mind that the repair process may vary based on the car. For instance, what can fix a P0354 code in a Ford may not be as effective against a P0354 code in a Jeep.

Narrow down your research to the documented fixes that are specific to your vehicle’s make and model.

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About The Authors
Written By Automotive and Tech Writers

The Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Reviewed By Technical Reviewer at

Richard McCuistian has worked for nearly 50 years in the automotive field as a professional technician, an instructor, and a freelance automotive writer for Motor Age, ACtion magazine, Power Stroke Registry, and others. Richard is ASE certified for more than 30 years in 10 categories, including L1 Advanced Engine Performance and Light Vehicle Diesel.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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We got this code on my 2008 Toyota Sienna a few months ago, right after we had all the spark plugs replaced. My husband changed the coil in the front middle. 2 days ago, on a cold start, my van started to idle very rough and my CE light started to flash. I turned off and a few hours later my husband started it to check the codes and no CE light. We did get the code P0304. I’m so confused. Can you shed some light on this? In the past 2 years we’ve had a new (used) transmission replaced, another one 6 months later, then a new alternator about a year after that.
Thanks so much!

Don't lyons

I have a po354 code on a 07 Mazda CX-9

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