OBD-II code · Powertrain (generic)
P0051 HO2S Heater Control Circuit Low (Bank 2 Sensor 1)
HO2S Heater Control Circuit Low (Bank 2 Sensor 1): the control-circuit voltage is below the expected range. The heater brings the oxygen sensor to operating temperature for closed-loop fuel control.
Is it safe to drive with P0051?
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)
- P0037HO2S Heater Control Circuit Low (Bank 1 Sensor 2)
- P0057HO2S Heater Control Circuit Low (Bank 2 Sensor 2)
- P004ETurbocharger/Supercharger Boost Control A Circuit Intermittent/Erratic
- P004FTurbocharger/Supercharger Boost Control B Circuit Intermittent/Erratic
- P0050HO2S Heater Control Circuit (Bank 2 Sensor 1)
- P0052HO2S Heater Control Circuit High (Bank 2 Sensor 1)
- P0053HO2S Heater Resistance Bank 1 Sensor 1
- P0054HO2S Heater Resistance Bank 1 Sensor 2
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.