P0137 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.
DTC/P0137·BMW
P0137 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeveritySafe to drive (short-term)BMW
P0137 on a BMW 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 BMW€63 - €434
What does P0137 mean on a BMW?
BMW 3 Series
2006–2024On N52 and N55 engines, the integrated exhaust manifold/catalyst design means any exhaust leak between cat and sensor usually involves a 200+ euro manifold gasket job. The downstream sensor itself is straightforward to reach from under the car. BMW OEM Bosch sensors run 110–200 euros, aftermarket Bosch (identical) around 60–110 euros.
What causes P0137 on a BMW?
Beyond the generic causes listed on the main P0137 page, these are the BMW-specific patterns we see most often:
BMW 3 SeriesManifold-to-downpipe gasket leak on N52/N55 letting fresh air reach the sensor
BMW 3 SeriesConnector corrosion from heat cycling on 10+ year old cars
How to diagnose P0137 on a BMW 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 BMW? (EUR)
Estimated repair costs on a BMW (BMW parts and labour typically run 40% above the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0137 on BMW
These codes commonly cluster with P0137 on BMW vehicles:
FAQ: P0137 on BMW
Can I drive with P0137?
Yes, for short distances. The downstream sensor does not directly control fuel injection, so the car will run normally. Long term, the low signal often masks a developing exhaust leak or converter issue that should be addressed.
Can an exhaust leak cause P0137?
Yes. Even a small leak between the catalytic converter and the downstream sensor lets fresh air reach the sensor, which it reads as a lean exhaust and reports as low voltage. Check for cracked welds, loose clamps, and worn gaskets before replacing the sensor.
Will a bad O2 sensor damage the catalytic converter?
Not the downstream sensor by itself. P0137 alone does not change fuel mixture significantly. But if the underlying cause is a real lean condition or a failing upstream sensor, that can damage the converter over time.
How much does it cost to fix P0137 in Europe?
Replacing the downstream sensor at an independent garage typically costs 100–250 euros total. Dealership pricing runs 200–400 euros, mostly due to OEM-branded sensors versus identical Bosch or NTK aftermarket units.
Looking for the full P0137 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0137 guideSkanyx · BMW
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