OBD-II code · Powertrain (generic, extended)
P22B9 O2 Sensor Positive Current Control Circuit Low (Bank 2 Sensor 2)
O2 positive current line on bank 2 sensor 2 stuck low — 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 P22B9?
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
- P22ACO2 Sensor Positive Current Control Circuit Low (Bank 1 Sensor 2)
- P22B6O2 Sensor Pumping Current Trim Circuit Low (Bank 1 Sensor 2)
- P22B7O2 Sensor Pumping Current Trim Circuit High (Bank 1 Sensor 2)
- P22B8O2 Sensor Positive Current Control Circuit/Open (Bank 2 Sensor 2)
- P22BAO2 Sensor Positive Current Control Circuit High (Bank 2 Sensor 2)
- P22BBO2 Sensor Reference Voltage Circuit/Open (Bank 2 Sensor 2)
- P22BCO2 Sensor Reference Voltage Performance (Bank 2 Sensor 2)
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.