P0137 on a Volkswagen: Causes, Fixes & Repair Cost

🟢 Low severity · drivable

Safe to drive — this downstream sensor only monitors the catalytic converter, so a VW with P0137 can be driven while you arrange the repair.

What P0137 means on a Volkswagen

On a Volkswagen, P0137 means the engine computer sees low voltage from the bank 1 downstream oxygen sensor behind the catalytic converter. This sensor only monitors converter efficiency, so low voltage usually means a faulty sensor, damaged wiring, or an exhaust leak — not a lean fuel mixture. Most VWs use a single bank, so bank 1 covers the whole engine.

Is P0137 common on Volkswagens?

P0137 appears on higher-mileage VWs as the downstream sensor ages and exhaust heat hardens its wiring. Small exhaust leaks near the sensor are a common trigger on older Golf and Jetta models, and the usual fix is an OE-quality Bosch sensor.

Commonly reported on: Golf, Jetta, Passat, Tiguan.

Symptoms

Check engine light on
Usually no change in how it drives
Possible exhaust tick from a small leak
Slightly worse fuel economy if a leak is present

Common causes

most common: Faulty bank 1 downstream oxygen sensor
common: Exhaust leak before the downstream sensor
common: Wiring damaged by exhaust heat
less common: Loose or corroded sensor connector

How to fix it

Fix	DIY?	Typical cost
Replace the bank 1 downstream oxygen sensor with a Bosch or OE-quality part	Yes	$70–250
Repair an exhaust leak near the sensor	Mechanic	$80–300
Repair or replace damaged O2 sensor wiring	Mechanic	$70–220