P0352 on Subaru: How to Diagnose & Fix
Ignition Coil B Primary/Secondary Circuit Malfunction
1 Subaru model · 1 documented issue · $60-$350 repair
P0352 on Subaru by model: symptoms, diagnosis and fix
Coil-on-plug ignition coils on the Forester are a common failure point. As the coil's internal epoxy/resin cracks with heat and age, the coil produces erratic or insufficient spark, causing single-cylinder misfires, rough idle, hesitation on acceleration, reduced fuel economy and a flashing/steady check-engine light. A frequently reported pattern is hard starting or stumbling when cold (below roughly 10°F) that improves once the engine warms. Note that a leaking spark plug tube seal (oil in the plug well) can prematurely kill a coil, so the two issues often appear together.
Common Symptoms
- Rough idle and vibration at idle
- Engine hesitation or stumble on acceleration
- Flashing or steady check engine light
- Hard starting or misfire when cold
- Reduced fuel economy
How to Fix
Pull codes — P0301-P0304 indicate the misfiring cylinder; P0351-P0354 indicate coil circuit faults. Confirm by swapping the suspect coil to an adjacent cylinder; if the misfire follows the coil, replace it (coils cannot be repaired). Inspect the plug well for oil and replace the spark plug tube seal if oil is present so the new coil isn't ruined. Replace the spark plugs at the same time. Forester ignition coil part numbers vary by year/engine (for example 22433AA691 on 2013-2018 2.5L and 22433AA590 on non-turbo 2009-2010); confirm the exact PN by VIN.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Subaru 22433AA590 Ignition Coil
single-cylinder replacement after the coil is proven failed Fitment/availability: 2009-2010 Forester 2.5L naturally aspirated X/X Limited/XS branch only; not XT, confirm VIN Fitment/availability: Add to Cart live when reviewed
- Genuine Subaru 22433AA630 Ignition Coil
single-cylinder replacement after the coil is proven failed Fitment/availability: 2011-2013 Forester 2.5L naturally aspirated X/X Limited/X Premium branch; not XT, confirm VIN Fitment/availability: ships in 1-2 business days with Add to …
- Genuine Subaru 22433AA682 Ignition Coil
single-cylinder replacement after the coil is proven failed Fitment/availability: 2014-2016 Forester 2.5i naturally aspirated branch; current replacement for 22433AA681/AA680, confirm VIN Fitment/availability: ships in 1-2 business days …
- Genuine Subaru 22433AA700 Ignition Coil
single-cylinder replacement after the coil is proven failed Fitment/availability: 2017-2018 Forester 2.5i naturally aspirated branch in this issue; retailer also catalogs XT, confirm VIN Fitment/availability: Add to Cart live when reviewed
- Genuine Subaru 22433AA770 Ignition Coil
single-cylinder replacement after the coil is proven failed Fitment/availability: 2019-2021 Forester Base/Premium/Sport/Limited/Touring branch; confirm VIN and production split Fitment/availability: ships in 1-3 business days with Add to…
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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 Subaru?
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 Subaru it is documented across 1 model: Forester.
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 Subaru?
Published repair estimates on Subaru range from $60 to $350 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.
Looking for P0352 on a different make?
View P0352 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.