P0351 on Subaru
Ignition Coil A Primary/Secondary Circuit Malfunction
P0351 on Subaru vehicles indicates ignition coil a primary/secondary circuit malfunction. Au7o has documented this code across 1 Subaru model — most commonly on Forester. P0351 indicates the engine computer found a fault in the primary or secondary circuit of ignition coil 'A' (typically the coil for cylinder 1 or the first coil in the firing system). The PCM monitors the coil's control circuit, and when the electrical feedback doesn't match what it expects during firing, it sets this code. Because the coil creates the high-voltage spark, this often causes a misfire, rough idle, hesitation, or loss of power. It is a circuit/component fault for one specific coil rather than a general engine problem. Typical repair costs on Subaru range from $60 to $350, depending on the specific model and root cause.
Common Causes of P0351
- •Failed or weak ignition coil
- •Damaged or corroded coil connector or pigtail
- •Broken or shorted wiring in the coil control circuit
- •Loss of power feed or ground to the coil
- •Worn or fouled spark plug overloading the coil
- •Failed coil driver inside the PCM/ECM
P0351 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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View P0351 across all makes →Frequently Asked Questions
What does P0351 mean on Subaru?▼
P0351 stands for "Ignition Coil A Primary/Secondary Circuit Malfunction." P0351 indicates the engine computer found a fault in the primary or secondary circuit of ignition coil 'A' (typically the coil for cylinder 1 or the first coil in the firing system). The PCM monitors the coil's control circuit, and when the electrical feedback doesn't match what it expects during firing, it sets this code. Because the coil creates the high-voltage spark, this often causes a misfire, rough idle, hesitation, or loss of power. It is a circuit/component fault for one specific coil rather than a general engine problem. On Subaru specifically, this code is documented across 1 model.
What causes P0351 on Subaru vehicles?▼
Common causes on Subaru: Failed or weak ignition coil, Damaged or corroded coil connector or pigtail, Broken or shorted wiring in the coil control circuit, Loss of power feed or ground to the coil, Worn or fouled spark plug overloading the coil. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0351 on a Subaru?▼
Repair costs on Subaru range from $60 to $350, depending on the specific model and root cause.
Which Subaru models have P0351 documented?▼
Au7o has documented P0351 on 1 Subaru model: Forester.