OBD-II code · Powertrain (generic, extended)
P22B1 O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 2)
O2 reference voltage on bank 1 sensor 2 above upper plausibility — short to B+. 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 P22B1?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to B+
- Less likelyConnector pins corroded - high contact resistance
- Less likelySupply wire pinched against B+ source
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
- P2246O2 Sensor Reference Voltage Circuit High (Bank 1 Sensor 1)
- P2250O2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 1)
- P22AEO2 Sensor Reference Voltage Circuit/Open (Bank 1 Sensor 2)
- P22BEO2 Sensor Reference Voltage Circuit High (Bank 2 Sensor 2)
- P22AFO2 Sensor Reference Voltage Performance (Bank 1 Sensor 2)
- P22B0O2 Sensor Reference Voltage Circuit Low (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)
- P22B4O2 Sensor Negative Current Control Circuit High (Bank 1 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.