Ignition Coil D Primary/Secondary Circuit Malfunction (Cylinder 4)
The P0354 code means the vehicle's onboard diagnostic system has detected: Ignition Coil D Primary/Secondary Circuit Malfunction (Cylinder 4). This is a moderate severity code.
- Keep driving?
- Short distances only
- DIY difficulty
- easy
- Estimated cost
- $50 - $300 (parts and labor)
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Common Symptoms
- Engine misfire on cylinder 4
- Rough idle and vibration
- Check Engine Light illuminated or flashing
- Reduced power and hesitation
- Poor fuel economy
Probable Causes (Ranked by Likelihood)
- Faulty ignition coil on cylinder 4 Very High
- Worn or fouled spark plug on cylinder 4 High
- Damaged coil connector or wiring High
- PCM coil driver circuit failure for cylinder 4 Moderate
- Water intrusion in spark plug well Low
Common Fixes by Vehicle
What techs usually find when diagnosing P0354 on specific vehicles — tap your vehicle for the fix and the exact part:
2009-2019 Ford F-150 5.0L Coyote Easy DIY
Coil #4 on the 5.0L Coyote is prone to failure from engine vibration cracking the internal windings. Replace with an OE-quality Motorcraft unit coil. Swap plugs to Motorcraft at the same time -- these are one-time-use plugs that can break on removal if over-torqued. Confirm the exact part for your year and engine with a retailer's fitment lookup or your VIN before ordering - these applications split by engine and build date.
Labor: 0.5-1 hour2011-2018 Chrysler Town & Country 3.6L Moderate DIY
Cylinder 4 coil failure on the 3.6L Pentastar is often accompanied by a cracked spark plug boot that allows arcing. Replace the coil and boot together with an OE-quality Mopar unit. Check the spark plug for fouling and replace with the OE plug for the 3.6L (Mopar / Champion RER8ZWYCB4) gapped to 0.043 inch. Confirm the exact part for your year and engine with a retailer's fitment lookup or your VIN before ordering - these applications split by engine and build date.
Labor: 0.5-1 hour2013-2020 Ford Escape 1.6L/2.0L EcoBoost Moderate DIY
Cylinder 4 coil on the rear bank is hard to access on the EcoBoost Escape. Use a coil-on-plug boot removal tool to avoid breaking the boot. Replace with an OE-quality Motorcraft unit and inspect the wiring harness for heat damage from the turbo exhaust manifold. Confirm the exact part for your year and engine with a retailer's fitment lookup or your VIN before ordering - these applications split by engine and build date.
Labor: 1-1.5 hoursFrequently Asked Questions
Can I drive with code P0354?
You can drive short distances with a steady Check Engine Light. A flashing light means catalytic converter damage is imminent -- stop driving immediately.
Can oil in the spark plug well cause P0354?
Yes. A leaking valve cover gasket can allow oil to pool around the coil boot in the spark plug well, causing the coil to short out or the spark to arc to ground instead of the plug.
How long do ignition coils typically last?
Ignition coils typically last 80,000-100,000 miles. However, they can fail earlier if spark plugs are not replaced on schedule, as worn plugs force coils to work harder.
Mechanics Guide Step-by-step diagnosis
Step-by-Step Diagnostic Procedure
-
Swap cylinder 4 ignition coil with another cylinder -- if the misfire code moves, the coil is faulty
-
Inspect the spark plug on cylinder 4 for wear, oil fouling, or damage
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Measure coil resistance -- primary 0.4-2.0 ohms, secondary 6,000-15,000 ohms
-
Check the spark plug well for water or oil contamination that may cause misfires
-
Test the PCM coil driver signal at the connector
Sources 2
This page is built from documented references. Verify against your own service info before repair work.
- SAE J2012Diagnostic Trouble Code Definitions (defines the generic OBD-II code ranges)
- Cross-checked against the SAE J2012:2002 DTC table (2026-08-27)archived scan of the SAE standard — readable copy, not SAE’s current edition
Commonly Affected Vehicles
- 2007-2017 Toyota Corolla
- 2008-2018 Honda Civic
- 2005-2015 Ford Focus
- 2010-2020 Hyundai Elantra
- 2009-2019 Chevrolet Cruze
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