The Quick Answer above is the generic definition. What follows is what is documented for the Mercedes-Benz models that log P0137, checked against manufacturer data and owner reports.
DTC/P0137·Mercedes-Benz
P0137 on Mercedes-Benz: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)Mercedes-Benz
P0137 on a Mercedes-Benz means the downstream oxygen sensor on Bank 1 (post-catalyst, Sensor 2) is reporting a voltage that stays too low for too long. This typically indicates a lean exhaust condition reaching the sensor, an exhaust leak ahead of the sensor, or a failed sensor stuck at low voltage. The downstream sensor should read a relatively steady 0.6–0.8V when the catalytic converter is working properly.
Repair cost on Mercedes-Benz€45 - €310
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Mercedes C-Class
2007–2024The W204 M271 1.8L Kompressor frequently triggers P0137 around 100,000–130,000 km from standard sensor wear. The W205 OM651 diesel has a known harness chafing point near the gearbox mount that produces intermittent low-voltage signals, which often returns after sensor replacement until the harness is also fixed. Mercedes-OEM sensors 130–220 euros, aftermarket Bosch around 70–120 euros.
What causes P0137 on a Mercedes-Benz?
Beyond the generic causes listed on the main P0137 page, these are the documented Mercedes-Benz-specific patterns:
Mercedes C-ClassStandard sensor wear on W204 M271 at 100,000+ km
Mercedes C-ClassHarness chafing on W205 OM651 diesel near gearbox mount
How to diagnose P0137 on a Mercedes-Benz with OBD2
Follow these steps to pinpoint the root cause of P0137:
- Read freeze frame data and check for any companion codes (P0420, P0171, P0174) that suggest a lean condition or converter problem
- Inspect the exhaust system between the catalytic converter and the downstream sensor for cracks, loose clamps, or leaking gaskets
- Inspect the Bank 1 Sensor 2 connector and wiring for corrosion, heat damage, or chafing
- Use a scan tool to view downstream sensor voltage. A healthy sensor reads around 0.6–0.8V steady. A reading stuck below 0.2V points to sensor failure or an exhaust leak
- Substitute a known-good sensor or swap with the Bank 2 downstream sensor if equipped. If the low voltage follows the sensor, the sensor is faulty
How much does P0137 cost to fix on a Mercedes-Benz? (EUR)
Estimated repair costs for P0137 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 P0137 on Mercedes-Benz
These codes commonly cluster with P0137 on Mercedes-Benz vehicles:
Looking for the full P0137 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0137 guideSkanyx · Mercedes-Benz
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