P0352 on Ford: How to Diagnose & Fix
Ignition Coil B Primary/Secondary Circuit Malfunction
1 Ford model · 1 documented issue · $120-$900 repair
P0352 on Ford by model: symptoms, diagnosis and fix
Explorers (especially the Sport and Platinum) with the twin-turbocharged 3.5L EcoBoost are widely reported to develop cylinder misfires, a flashing check-engine light, rough idle and a loss of power that owners frequently chase by replacing ignition coils and spark plugs. The turbocharged, high-heat environment is hard on plugs; the factory Motorcraft SP-534 plug wears its ground strap prematurely and the Explorer's 3.5L EcoBoost is direct-injection only (no port injection), so intake-valve carbon buildup aggravates misfires. A recurring root cause traced on the forums is broken/seized exhaust manifold studs that create a vacuum-style exhaust leak right at the cylinder head, which repeatedly destroys coils and triggers misfire codes until the bolts are addressed. Ford never issued a recall for the manifold studs.
Common Symptoms
- Flashing or steady check-engine light
- Cylinder misfire / rough idle
- Loss of power or hesitation under boost
- Ticking/exhaust-leak noise on cold start
- Repeated coil failures after replacement
How to Fix
Replace all six spark plugs with the updated Motorcraft SP-580 (supersedes SP-534, pre-gapped to ~0.032 in) and renew failed coil-on-plug units; do plugs as a set on or before the 60,000-100,000 mi interval (severe-duty/towing service much sooner). If misfires recur after coil/plug replacement, inspect for broken exhaust manifold studs/bolts and an exhaust leak at the head and replace the studs. Adding a catch can and the updated SP-580 plug reduces fouling on these direct-injection-only engines.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Ignition CoilCross-refGN10237
Fitment confirmed against the ShowMeTheParts catalog for this vehicle's year and engine.
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Sources for this issue (3)
P0352 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0352 mean on a Ford?
P0352 stands for "Ignition Coil B Primary/Secondary Circuit Malfunction." This is an ignition/engine code. Each ignition coil takes the car's low battery voltage and steps it up into the high-voltage spark that fires a spark plug. P0352 means the engine computer detected a problem in the primary or secondary circuit of ignition coil 'B' — it isn't getting the proper electrical signal back when the coil is commanded to fire. This often causes a misfire, rough running, hesitation or reduced power, and if left unaddressed can lead to unburned fuel damaging the catalytic converter. On Ford it is documented across 1 model: Explorer.
What are the most common causes of P0352?
The most common causes of P0352 are: Failed ignition coil 'B', Damaged wiring or corroded connector at the coil, Open or short in the coil primary/secondary circuit, Worn or fouled spark plug increasing coil stress, Poor power or ground supply to the coil, Faulty ignition control circuit/driver in the ECM (less common). The specific cause varies by vehicle.
How much does it cost to fix P0352 on a Ford?
Published repair estimates on Ford range from $120 to $900 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.