Picture this:
Your car is misfiring and struggling to accelerate with a lit check engine light.
You plug in your OBD II scanner, hoping for a quick answer, and it throws you an unfamiliar code — P0354.
What does it mean?
Is it something serious?
Keep reading to find out all the answers, along with the possible solutions and its warning signs, so you can spot the trouble before it gets serious under the hood.
This Article Contains:
- What Is the P0354 Code?
- What Causes the P0354 Error Code?
- What Are the Common Symptoms of the P0354 Code?
- Is P0354 a Critical Code?
- How to Diagnose and Fix Fault Code P0354
- How to Avoid a P0354 Error Code
What Is the P0354 Code?
OBD code P0354 stands for “Ignition Coil D Primary or Secondary Circuit Malfunction.”
Code P0354 is a generic Diagnostic Trouble Code (DTC), meaning it applies to all vehicle makes and models, though the specific diagnostic and repair steps may vary.
This code indicates that the Powertrain Control Module (PCM) or Engine Control Module (ECM) has spotted an issue in the primary or secondary electrical circuit of ignition coil ‘D’.
The ignition coil converts low battery volts into high volts to fire the spark plug. The circuit delivers power and control signals between the coil and the engine computer.
So, how is the OBD code P0354 triggered?
The error occurs when the ECM or PCM fails to detect a voltage spike in ignition coil D’s primary winding.
Usually, when the battery current to the primary coil is switched off, it generates a high-voltage spike in both primary and secondary windings, which powers the spark plug. If this spike is missing or abnormal, often due to high resistance in the coil, the system assumes the ignition coil isn’t functioning properly.
In some vehicles, such as those from Toyota Motor Corporation, the ECM may even cut off the fuel injector for the affected cylinder using an Ignition Confirmation Signal (IGF). This helps prevent further issues, like engine damage or misfires, in case of ignition failure.
NOTE: The last digit of the error code represents the affected cylinder number. For example:
- P0351 points to a problem in the ignition coil of cylinder 1
- P0353 indicates an issue with ignition coil C on cylinder 3
Next, we’ll explore the possible reasons behind this trouble code.
What Causes the P0354 Error Code?
From a faulty coil to PCM failure, here are a few issues that can trigger the fault code P0354:
- A faulty ignition coil or ignition coil circuit
- Bad coil pack
- Short or open coil-on-plug driver circuit (COP driver circuit)
- Defective spark plug
- Leak in the intake manifold
- Idle air control valve malfunction
- Broken ignition coil connector lock
- Blockage in air passages of the throttle body due to carbon buildup
- Loose connection at the ignition coil connector or the ECM/PCM connector
- ECM or PCM failure, including issues like poor PCM grounds
Read on to learn the warning signs of the P0354 trouble code so you can spot it quickly.
What Are the Common Symptoms of the P0354 Code?
Your car could be trying to warn you about a DTC P0354 if there’s:
- An illuminated check engine light
- Sluggish acceleration
- Rough idling and vibrations while driving
- Power loss, especially under heavy engine load
- Difficulty starting the engine
- Engine misfires on acceleration
NOTE: In some rare cases, there may not be any warning signs.
If you’re wondering how serious this code really is — we’ve got you covered.
Is P0354 a Critical Code?
Short answer — yes.
The P0354 DTC gets logged when proper ignition doesn’t occur in a specific cylinder number. This can lead to the following:
- The other cylinders in the engine work harder to compensate for the power loss.
- The engine misfires intermittently, which can damage or clog the catalytic converter.
- Drivability issues can compromise your road safety.
Read on to find out how to fix these issues before it leaves you stranded.
How to Diagnose and Fix Fault Code P0354?
Diagnosing and repairing code P0354 requires good automotive knowledge and skills. That’s why you should leave the work to an expert mechanic.
To find out what caused the P0354 DTC, a mechanic will:
- Take your vehicle for a test drive. If an engine misfire occurs, it suggests a possible issue with the ignition coil circuit.
- Perform a resistance test on the coil pack and see if there’s a wiring issue.
- Check if the coil pack wiring harness has a proper ground supply.
- Inspect the condition of the spark plug connected to the ignition coil.
- Look at the intake manifold for signs of a vacuum leak.
- Check if the ECM or PCM control circuit is working as expected.
- Examine the Hertz signal in the coil circuit to confirm that the ECM or PCM is sending the proper signal.
- Check whether the throttle body has carbon buildup or whether the sensor works properly.
- Inspect the ignition coil connector for corrosion, loose pins, or damaged wires, and test for proper voltage and continuity using a multimeter.
- Check the ECM or PCM connector and ignition coil connector for loose connections.
- Verify that the wiring harness connecting the coil pack to your ECM or PCM doesn’t show signs of fraying, corrosion, or melting. If all external components check out, the issue might be due to the faulty PCM coil driver, requiring further diagnostic testing.
Here are some possible solutions your mechanic will consider to fix the DTC P0354:
- Replace the defective ignition coil (or the coil driver circuit)
- Replace the bad coil pack
- Replace the damaged spark plug
- Repair the vacuum leak in the intake manifold
- Replace the throttle body
- Replace the ignition wiring connector (electrical connector)
- Repair or replace the wire harness between the coil pack and the ECM or PCM. If necessary, the mechanic might also replace the faulty PCM coil driver.
- Restore or replace the malfunctioning PCM or ECM
After completing the repairs, the mechanic will perform a test drive to ensure the code doesn’t return.
However, you don’t need to go through such trouble if you maintain your vehicle well.
How to Avoid a P0354 Error Code
To prevent a P0354 error code:
- Regularly inspect and replace fuel ignition coils as per the manufacturer’s recommendations.
- Ensure spark plugs and plug wires are in good condition to prevent excessive coil strain.
- Inspect wire harnesses and connectors for corrosion, frayed wires, or loose connections. The mechanic may replace damaged wires to maintain electrical flow and continuity.
- Avoid aggressive driving, such as rapid acceleration or hard braking, as these can strain ignition components.
- Maintain proper coolant levels and ensure the radiator and cooling fan function properly.
- Avoid prolonged idling to prevent excessive heat buildup in the engine bay.
- Keep ignition components dry and clean to prevent moisture-related electrical shorts.
Fix Code P0354 Hassle-Free with AutoNation Mobile Service
The P0354 trouble code on your OBD II scanner points to an ignition coil issue, often leading to misfires and a noticeable drop in engine performance. Since multiple factors can trigger this code, it’s best to have a professional take a closer look.
That’s where AutoNation Mobile Service comes in.
We’re a mobile auto repair service company that offers services every day of the week. Our repairs are also backed by a 12-month, 12,000-mile warranty for extra peace of mind.
Contact us for an easy online booking, and our expert mechanics will take care of any repairs and error codes right from your driveway.