The Quick Answer above is the generic definition. What follows is what is documented for the Mercedes-Benz models that log P0136, checked against manufacturer data and owner reports.
DTC/P0136·Mercedes-Benz
P0136 on Mercedes-Benz: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Mercedes-Benz
P0136 on a Mercedes-Benz means the downstream oxygen sensor on Bank 1 (post-catalyst, Sensor 2) is producing a voltage signal outside the expected operating range. This sensor monitors how well the catalytic converter is cleaning exhaust gases. A failing sensor or a degrading converter can both trigger this code.
Repair cost on Mercedes-Benz€45 - €310
Connect any standard Bluetooth OBD2 adapter to your Mercedes-Benz and Skanyx tells you what P0136 means on that engine, whether it is safe to keep driving, and what the fix should cost. Free on iPhone and Android.
Get Skanyx freeWhat does P0136 mean on a Mercedes-Benz?
Mercedes C-Class
2007–2024The W204 M271 1.8L Kompressor commonly throws P0136 around 100,000–130,000 km from standard sensor aging. The W205 with the OM651 diesel has a known sensor harness chafing issue where the loom rubs against the gearbox mount, causing intermittent signal faults. Mercedes-OEM Bosch sensors are 130–220 euros, aftermarket Bosch around 70–120 euros.
What causes P0136 on a Mercedes-Benz?
Beyond the generic causes listed on the main P0136 page, these are the documented Mercedes-Benz-specific patterns:
Mercedes C-ClassStandard sensor wear on W204 M271 at 100,000+ km
Mercedes C-ClassSensor harness chafing on W205 OM651 diesel near gearbox mount
How to diagnose P0136 on a Mercedes-Benz with OBD2
Follow these steps to pinpoint the root cause of P0136:
- Read freeze frame data to capture the engine conditions when the code was set (RPM, coolant temp, load)
- Inspect the exhaust system between the catalytic converter and the downstream sensor for cracks, loose clamps, or gasket leaks
- Inspect the Bank 1 Sensor 2 connector and wiring for corrosion, heat damage, or chafing against the heat shield
- Use a scan tool to view live O2 sensor data. The downstream sensor should show a relatively flat voltage around 0.6–0.8V at operating temperature, not the rapid switching of the upstream sensor
- Compare upstream vs downstream waveforms. If both switch identically, the converter is likely failing. If the downstream is erratic or stuck, replace the sensor
How much does P0136 cost to fix on a Mercedes-Benz? (EUR)
Estimated repair costs for P0136 in EUR, compiled across makes. Expect Mercedes-Benz parts and labour towards the upper end of each range.
Prices estimated as of March 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0136 on Mercedes-Benz
These codes commonly cluster with P0136 on Mercedes-Benz vehicles:
Looking for the full P0136 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0136 guideSkanyx · Mercedes-Benz
Diagnose P0136 on your Mercedes-Benz
Your car logged P0136. Skanyx reads it on any standard Bluetooth OBD2 adapter, tells you whether it is safe to keep driving, and shows the €45-€310 repair range so you know the number before a shop quotes you. Free on iPhone and Android, and you do not need to be a mechanic to read it.
Get Skanyx free