Mercedes-Benz P0301

Cylinder 1 misfire on Mercedes — M271/M272/M274 coil packs, injectors and timing chain wear are the headline causes.

Mercedes-Benz P0301 — Cylinder 1 misfire on Mercedes — M271/M272/M274 coil packs, injectors and timing chain wear are the headline causes. Typical UK independent garage cost: £100–£1800.

What actually causes P0301 on a Mercedes-Benz

Mercedes M271 1.8 cars are well-known for camshaft adjuster bolt and balance shaft issues that can cause cylinder-specific misfires alongside timing chain wear. M272 V6 suffered idler gear wear that throws misfires. M274 typically suffers coil pack failures and direct injection carbon. Always investigate timing chain on M271 if misfire is paired with chain rattle.

Mercedes-Benz engines that log P0301

• M271 1.8 supercharged (C-Class, E-Class)
• M272 3.5 V6
• M274 2.0 turbo (C-Class, E-Class)
• M276 3.5 V6

How we diagnose P0301 on a Mercedes-Benz

1. Swap coil pack cylinder-to-cylinder to confirm
2. Read spark plug and check for fouling pattern
3. On M271, check for chain rattle and timing chain wear via Xentry data
4. On M272 V6, check for idler gear wear if multiple misfires across cylinders
5. Compression and leak-down test if no obvious electrical cause

The common misdiagnosis to avoid

On M271, P0301 alongside cold-start chain rattle is a chain investigation, not a coil swap — balance shaft and chain wear are well-documented.

Mercedes-Benz P0301 repair cost in the UK

Expect £100–£1800 including parts and labour at an independent garage. Main-dealer quotes on Mercedes-Benz are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Service campaign / TSB note

Mercedes M272/M273 balance shaft and idler gear service campaigns.

Bob's workshop tip

Mercedes V6 M272 idler gear is a known job — if multiple cylinder misfires across the engine, plan for engine-out work, not chase individual coils.

Codes usually seen alongside P0301 on Mercedes-Benz

• P0300
• P0302
• P0303
• P0304

Symptoms drivers report with P0301

• Engine 'juddering' like a wet dog when you try to overtake on the A9.
• The car 'kangaroos' at low speeds, especially when the engine is stone cold.
• The EML (Engine Management Light) is flashing at you—that's a 'stop now' warning for your catalytic converter.
• A distinct 'put-put-put' sound from the exhaust pipe at idle.
• Massive loss of power, feels like you're towing a caravan that isn't there.

Repairs that clear P0301

• Replace spark plug
• Swap coil pack
• Injector test
• Compression test

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0301 guide.

Reading P0301 on a Mercedes-Benz properly

A generic reader will show P0301 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Mercedes-Benz has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.

Clearing P0301 without fixing it

Erasing the code resets the Mercedes-Benz's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.

Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0301 is showing on your Mercedes-Benz, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.