P0303 on Peugeot
Cylinder 3 Misfire Detected
P0303 on Peugeot vehicles indicates cylinder 3 misfire detected. Au7o has documented this code across 1 Peugeot model — most commonly on 308. This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. Typical repair costs on Peugeot range from $350 to $900, depending on the specific model and root cause.
Common Causes of P0303
- •Worn or fouled spark plug in cylinder 3
- •Failed or weak ignition coil on cylinder 3
- •Bad spark plug wire or boot (where applicable)
- •Clogged or leaking fuel injector for cylinder 3
- •Vacuum or intake air leak affecting that cylinder
- •Low compression (worn rings, burnt/leaking valve, head gasket)
- •Wiring or connector fault at the coil or injector
P0303 on Peugeot by Model
Peugeot 308(1 issue)
- 1.6 THP Intake Valve Carbon Buildup (Direct Injection)2008-2017
Because the turbocharged 1.6 THP (EP6DT/EP6CDT/EP6DTS) injects fuel directly into the cylinder, no fuel washes over the backs of the intake valves; oil vapour from the PCV system bakes onto the valves and ports as hard carbon. Deposits typically become symptomatic between 50,000 and 80,000 km, progressively restricting airflow and causing rough cold idle, cold-start misfires, poor throttle response and higher fuel consumption.
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View P0303 across all makes →Frequently Asked Questions
What does P0303 mean on Peugeot?▼
P0303 stands for "Cylinder 3 Misfire Detected." This code means your engine's computer detected a misfire specifically in cylinder number 3 — that cylinder isn't burning its fuel-air mixture properly or completely. The computer senses misfires by watching for tiny fluctuations in crankshaft speed each time a cylinder is supposed to fire. A misfire wastes fuel, can cause a noticeable shake, rough idle or loss of power, and can flood raw fuel into the exhaust where it may overheat and damage the catalytic converter. Because the fault is isolated to one cylinder, the cause is usually something specific to that cylinder's ignition, fuel delivery, or compression. On Peugeot specifically, this code is documented across 1 model.
What causes P0303 on Peugeot vehicles?▼
Common causes on Peugeot: Worn or fouled spark plug in cylinder 3, Failed or weak ignition coil on cylinder 3, Bad spark plug wire or boot (where applicable), Clogged or leaking fuel injector for cylinder 3, Vacuum or intake air leak affecting that cylinder. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0303 on a Peugeot?▼
Repair costs on Peugeot range from $350 to $900, depending on the specific model and root cause.
Which Peugeot models have P0303 documented?▼
Au7o has documented P0303 on 1 Peugeot model: 308.