P0141 on a Mercedes-Benz: Causes, Fixes & Repair Cost

🟢 Low severity · drivable

The car remains drivable because the heater only affects sensor warm-up speed, not engine performance.

What P0141 means on a Mercedes-Benz

On a Mercedes-Benz, P0141 points to a failed heater circuit in the bank 1 downstream oxygen sensor. The downstream sensor monitors the catalytic converter; without its heater it reads slowly until the exhaust warms it, but the engine keeps running normally.

Is P0141 common on Mercedes-Benzs?

This code shows up on higher-mileage Mercedes models like the C-Class, E-Class, and ML, usually because the sensor heater element gives out over time. Mercedes uses Bosch-style oxygen sensors, and OEM replacement parts cost more than on mainstream brands.

Commonly reported on: C-Class, E-Class, ML, GLK.

Symptoms

Check engine light is on
Emissions test may fail
Slightly lower fuel economy
No drivability problems

Common causes

most common: Heater element burned out inside the sensor
common: Blown fuse for the oxygen sensor heater circuit
common: Damaged wiring or connector at the rear sensor
rare: Failed engine computer control of the heater circuit

How to fix it

Fix	DIY?	Typical cost
Check the heater fuse and test the circuit with a multimeter first	Yes	$10–60
Replace the bank 1 downstream oxygen sensor	Yes	$90–280
Repair the wiring or connector feeding the sensor	Yes	$30–150
Have a shop replace the sensor including labor	Mechanic	$180–450