OBD-II code · Powertrain (generic)
P0037 HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
O2 sensor heater control circuit on bank 1, sensor 2 reports low voltage. Likely shorted to ground or open in the heater control wire. The heater warms the sensor element to operating temperature (~600 °C); without it the sensor stays inactive in closed loop and the ECM cannot trim mixture.
Is it safe to drive with P0037?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyHeater wire shorted to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Repair at a glance
- Difficulty
- Easy
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–1.5 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Oxygen Sensor Heater, Sensor Wiring
Related codes
- P0031HO2S Heater Control Circuit Low (Bank 1 Sensor 1)
- P0051HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
- P0057HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
- P0034Turbocharger Bypass Valve Control Circuit Low
- P0035Turbocharger Bypass Valve Control Circuit High
- P0036HO2S Heater Control Circuit (Bank 1 Sensor 2)
- P0038HO2S Heater Control Circuit High (Bank 1 Sensor 2)
- P0039Turbocharger/Supercharger Bypass Valve A Control Circuit Range/Performance
- P003ATurbocharger/Supercharger Boost Control A Position Exceeded Learning Limit
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.