P0175 on a Mercedes-Benz: Causes, Fixes & Repair Cost

🟠 Moderate severity · drivable

Drivable short-term, but a rich mixture can foul spark plugs and damage the catalytic converter if the code is ignored.

What P0175 means on a Mercedes-Benz

On a Mercedes, P0175 means the engine is running rich on bank 2 — the side opposite cylinder 1 on the V6 and V8 engines Mercedes uses. The computer has reduced fuel as far as it can and still sees too much fuel or too little air getting into the engine.

Is P0175 common on Mercedes-Benzs?

P0175 appears on Mercedes V6 and V8 models, commonly the C-Class, E-Class, and S-Class. Leaking fuel injectors and a dirty mass air flow sensor are frequent causes, along with a slow oxygen sensor. A fuel pressure regulator stuck high can also flood the mixture with fuel.

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

Symptoms

Check engine light is on
Poor fuel economy
Fuel smell from the exhaust
Rough idle or hesitation

Common causes

most common: Leaking fuel injector on bank 2
common: Dirty or failing mass air flow (MAF) sensor
common: Slow or failing oxygen sensor on bank 2
less common: Fuel pressure too high
less common: Clogged air filter

How to fix it

Fix	DIY?	Typical cost
Clean the MAF sensor with MAF cleaner spray	Yes	$10–20
Replace the leaking injector(s) on bank 2	Mechanic	$250–700
Replace the bank 2 upstream oxygen sensor	Yes	$80–250
Check fuel pressure and replace a stuck regulator	Mechanic	$150–400

Frequently asked questions

Which side is bank 2 on a Mercedes?

On V6 and V8 Mercedes engines, bank 1 is the side with cylinder 1 and bank 2 is the opposite side. This code means the rich condition is on that second bank.

Will cleaning the MAF sensor fix P0175 on a Mercedes?

Sometimes. If the MAF is dirty and reading low, cleaning it with MAF spray can restore the reading and clear the rich condition. If not, the sensor may need replacing.

How long can I drive with P0175 on a Mercedes?

Short trips are fine, but a rich mixture can foul spark plugs and damage the catalytic converter over time. Have it checked soon.