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
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
-
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
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 Motorcraft DG-542 coil. Swap plugs to Motorcraft SP-546 at the same time -- these are one-time-use plugs that can break on removal if over-torqued.
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 Mopar 56029129AB. Check the spark plug for fouling and replace with the OE plug for the 3.6L (Mopar SP149125AF / Champion RER8ZWYCB4) gapped to 0.043 inch.
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 Motorcraft DG-549 and inspect the wiring harness for heat damage from the turbo exhaust manifold.
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.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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