P0302 on a Mercedes-Benz: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

If the check engine light is flashing, stop driving — a severe misfire can damage the catalytic converter. A steady light is usually safe for a short drive to a shop.

What P0302 means on a Mercedes-Benz

On a Mercedes-Benz, P0302 means the engine computer has detected that cylinder 2 is not firing properly and is failing to contribute its share of power. Because it is a single-cylinder code, the fault is usually tied to cylinder 2 itself, such as its spark plug, ignition coil, or fuel injector.

Is P0302 common on Mercedes-Benzs?

P0302 appears on Mercedes four-cylinders and V6s like the 2.0L turbo in the C-Class and GLC and the 3.5L V6 in the E-Class and GLE. Mercedes ignition coils and spark plugs wear with mileage, and the parts carry a premium price. On direct-injection engines, carbon buildup on intake valves can also cause a stubborn single-cylinder misfire.

Commonly reported on: C-Class, E-Class, GLC, GLE.

Symptoms

Check engine light on (flashing if severe)
Rough idle or shaking at a stop
Loss of power or hesitation under acceleration
Poor fuel economy

Common causes

most common: Worn spark plug in cylinder 2
common: Failing ignition coil for cylinder 2
common: Clogged or leaking fuel injector in cylinder 2
less common: Carbon buildup on intake valves on direct-injection engines
less common: Low compression in cylinder 2 from engine wear

How to fix it

Fix	DIY?	Typical cost
Replace the spark plug in cylinder 2	Yes	$40–150
Replace the ignition coil for cylinder 2	Yes	$120–350
Replace the fuel injector in cylinder 2	Mechanic	$300–900
Have a shop clean intake valve carbon buildup	Mechanic	$400–900

Frequently asked questions

Is it safe to drive my Mercedes with a P0302 code?

Only if the light is steady and the car runs fine. A flashing light means a severe misfire, so stop driving and get it towed.

Why does my Mercedes misfire on cylinder 2?

Spark plugs and ignition coils are the usual causes on Mercedes engines. On direct-injection models, carbon buildup on the intake valves can also cause it.

How much does it cost to fix P0302 on a Mercedes-Benz?

Plugs and coils run about $40–$350. Injectors and carbon cleaning jobs cost more, so diagnose early to keep the bill down.