EngineLightCodes
Powertrain code

P0137 O2 Sensor Circuit Low Voltage Bank 1 Sensor 2

Severity
Fix soon
Typical repair cost
$70–$280
Do it yourself
Possible, easy
Shop time
0.3–1.5 hours

The oxygen sensor after the catalytic converter on bank 1 (sensor 2) is a switching sensor (about 0.1–0.9 V) used for converter monitoring and fine mixture trim.

How the engine computer detects it

P0137 means the signal stays below the lower limit. Documented limits: GM below 40–60 mV (two trips); Ford switches in a pull-up and reads open above 1 MΩ (20 kΩ from 2020) or short to ground below 10 Ω, within 10 s. Subaru uses the code as a functional test instead: the sensor never reaches 550 mV within 200 s after fuel cut-off, i.e. it behaves as if permanently lean – so a real exhaust leak can also trigger it there. When it fails, the control module stops the downstream trim and cannot evaluate the converter; there is no limp mode.

Written from public technical sources and not yet checked by a mechanic. How we write these pages

Symptoms

  • Check engine light on (usually after two drive cycles)
  • Catalyst monitor readiness not set
  • Usually no noticeable change in driving

Common causes

  1. Signal wire shorted to ground or melted against the exhaust Most likely
  2. Sensor faulty (cracked element, thermal shock from water) Most likely
  3. Signal circuit open (counts as low on Ford) Possible
  4. Exhaust leak ahead of the sensor (lean reading) Possible
  5. Signal and ground wires swapped after a repair Less likely

How to diagnose P0137

  1. Read every stored code with an OBD-II scanner. If misfire or fuel trim codes are there too, fix those first: they often cause this one.
  2. Inspect the parts involved: oxygen sensor bank1 sensor2, oxygen sensor wiring, catalytic converter.
  3. Work through the causes above from most to least likely, cheapest checks first.
  4. Clear the code and drive a full drive cycle to confirm the repair held.

Reading the code

P
Powertrain
0
Generic (SAE) code
1
Fuel and air metering
37
Specific fault

Questions drivers ask

Can I drive with code P0137?

Usually yes for a short time, if the car drives normally, the temperature gauge reads normal and the check engine light is steady. If the light flashes, the engine loses power or overheats, or other warning lights come on, pull over and have it checked.

Will my car pass an emissions inspection with P0137?

Probably not in states that test vehicles with an OBD-II scan: an emissions-related code that keeps the check engine light on is usually an automatic fail. Rules differ by state and county, so check yours.

Will P0137 clear by itself?

The light can go off after several drive cycles without the fault, but the code returns if the cause is still there. After a repair, the readiness monitors need a full drive cycle before an inspection.

Can I fix P0137 myself?

Often yes, with an OBD-II scanner and basic tools. Difficulty: easy. Start with the cheapest checks before replacing expensive parts.

Often reported together

Codes that owners mention in the same NHTSA complaints as P0137. They can point to a shared cause, so it's worth checking them together.

This page is general information, not a substitute for a professional diagnosis. Repair costs are rough estimates for parts and labor and vary by vehicle and region.