OBD-II code · Powertrain (generic, extended)
P22B0 O2 Sensor Reference Voltage Circuit Low (Bank 1 Sensor 2)
O2 reference voltage on bank 1 sensor 2 below lower plausibility — short to ground. A drifted or sluggish lambda sensor lets the mixture run lean or rich without correction — fuel economy and emissions suffer immediately.
Is it safe to drive with P22B0?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to ground
- Less likelyConnector pins corroded - high contact resistance
- Less likelyHarness chafing through insulation
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Oxygen Sensor
Related codes
- P2245O2 Sensor Reference Voltage Circuit Low (Bank 1 Sensor 1)
- P2249O2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 1)
- P22AEO2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 2)
- P22BDO2 Sensor Reference Voltage Circuit Low (Bank 2 Sensor 2)
- P22ADO2 Sensor Positive Current Control Circuit High (Bank 1 Sensor 2)
- P22AFO2 Sensor Reference Voltage Performance (Bank 1 Sensor 2)
- P22B1O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 2)
- P22B2O2 Sensor Negative Current Control Circuit/Open (Bank 1 Sensor 2)
- P22B3O2 Sensor Negative Current Control Circuit Low (Bank 1 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.