P0303 on Suzuki: How to Diagnose & Fix
Cylinder 3 Misfire Detected
1 Suzuki model · 1 documented issue · $200-$1,200 repair
P0303 on Suzuki by model: symptoms, diagnosis and fix
The K10B 1.0 3-cylinder in Alto, Celerio (early), Splash, and Wagon R uses shim-under-bucket valve adjustment — not the more common hydraulic lash adjusters. Suzuki specifies a check at 96,000 km but many owners (and dealers) skip it; tight valves over time cause burned exhaust valves and failed compression.
Common Symptoms
- rough idle
- misfire
- low compression
- reduced economy
How to Fix
Valve clearance check + adjustment at 96,000 km is in the service book — confirm it has been done. £200-£400 labor + shims. If skipped repeatedly, eventually a leak-down test will reveal valve burn — head rebuild £700-£1,200.
P0303 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 P0303 mean on a Suzuki?
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 Suzuki it is documented across 1 model: Alto.
What are the most common causes of P0303?
The most common causes of P0303 are: 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. The specific cause varies by vehicle.
How much does it cost to fix P0303 on a Suzuki?
Published repair estimates on Suzuki range from $200 to $1,200 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 P0303 on a different make?
View P0303 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.