P0354 on Subaru
Ignition Coil D Primary/Secondary Circuit Malfunction
P0354 on Subaru vehicles indicates ignition coil d primary/secondary circuit malfunction. Au7o has documented this code across 1 Subaru model — most commonly on Forester. This is an ignition/engine code. The ignition coil boosts low battery voltage into the high-voltage spark that ignites the air-fuel mixture. P0354 means the engine computer detected a fault in the primary or secondary circuit of ignition coil 'D' — the coil isn't returning the proper signal when it's told to fire. This commonly produces a misfire, rough running, hesitation or reduced power, and ongoing misfires can damage the catalytic converter over time. Typical repair costs on Subaru range from $60 to $350, depending on the specific model and root cause.
Common Causes of P0354
- •Failed ignition coil 'D'
- •Damaged wiring or corroded connector at the coil
- •Open or short in the coil primary/secondary circuit
- •Worn or fouled spark plug adding load to the coil
- •Poor power or ground supply to the coil
- •Faulty ignition driver in the ECM (less common)
P0354 on Subaru by Model
Subaru Forester(1 issue)
- Ignition Coil Failure Causing Misfire and Hard Cold-Weather Starting2009-2022
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.
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What does P0354 mean on Subaru?▼
P0354 stands for "Ignition Coil D Primary/Secondary Circuit Malfunction." This is an ignition/engine code. The ignition coil boosts low battery voltage into the high-voltage spark that ignites the air-fuel mixture. P0354 means the engine computer detected a fault in the primary or secondary circuit of ignition coil 'D' — the coil isn't returning the proper signal when it's told to fire. This commonly produces a misfire, rough running, hesitation or reduced power, and ongoing misfires can damage the catalytic converter over time. On Subaru specifically, this code is documented across 1 model.
What causes P0354 on Subaru vehicles?▼
Common causes on Subaru: Failed ignition coil 'D', Damaged wiring or corroded connector at the coil, Open or short in the coil primary/secondary circuit, Worn or fouled spark plug adding load to the coil, Poor power or ground supply to the coil. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0354 on a Subaru?▼
Repair costs on Subaru range from $60 to $350, depending on the specific model and root cause.
Which Subaru models have P0354 documented?▼
Au7o has documented P0354 on 1 Subaru model: Forester.