P0137 on BMW: Causes, Symptoms and Fix Cost
Quick Answer
Safe to drive (short-term)
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.
- Severity
- Moderate · Emissions
- Typical repair cost, all makes
- €45-€310
Connect a standard OBD2 adapter (Bluetooth LE on iPhone) to your BMW and Skanyx tells you what P0137 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 P0137 mean on a BMW?
The Quick Answer above is the generic definition. What follows is the model-specific detail for the BMW models that log P0137.
BMW 3 Series
2006-2024
On the N52 there are two downstream sensors, one after each catalytic converter (bank 1 = cylinders 1-3, bank 2 = cylinders 4-6), so P0137 is the bank 1 sensor. Any exhaust leak between the catalytic converter and that sensor, for example at a flange gasket, lets fresh air reach it. The downstream sensor itself is straightforward to reach from under the car and runs roughly 60 to 200 euros depending on where you buy it.
Source: bimmerworld.com, bimmerworld.com
Sources
- bimmerworld.com bimmerworld.com/Exhaust/O2-Sensors/BMW-Engine-Oxygen-Sensor-O2-11787545074.html
- bimmerworld.com bimmerworld.com/Exhaust/O2-Sensors/BMW-Engine-Oxygen-Sensor-O2-11787545075.html
What causes P0137 on a BMW?
Beyond the generic causes listed on the main P0137 page, these are the patterns noted for BMW models:
Exhaust flange or gasket leak between the catalyst and the sensor letting fresh air reach it
: BMW 3 Series
Connector corrosion from heat cycling on older cars
: BMW 3 Series
How to diagnose P0137 on a BMW with OBD2
- 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 for P0137 in EUR, compiled across makes. Expect BMW parts and labour towards the upper end of each range.
| Repair | Parts Cost | Labor Cost | Total Estimate | DIY Difficulty |
|---|---|---|---|---|
| Replace downstream O2 sensor (Bank 1, Sensor 2) | €40–€180 | €50–€130 | €90–€310 | Moderate |
| Fix exhaust leak near downstream sensor | €15–€90 | €60–€200 | €75–€290 | Moderate |
| Repair O2 sensor wiring or connector | €5–€25 | €40–€120 | €45–€145 | Moderate |
Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.
Codes related to P0137
These codes are often seen alongside P0137 or point to related issues, on any make:
Looking for the full P0137 reference (all makes, full diagnosis flow, complete repair cost matrix)? See the main P0137 guide