OBD-II code · Powertrain (generic, extended)
P2B89 Intake Air O2 Sensor Circuit Low Voltage Bank 1
Voltage on the intake air oxygen sensor signal line on bank 1 is below the expected window. 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 P2B89?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySignal wire shorted to ground
- PossibleInternal sensor short
- Less likelyConnector pins corroded - high contact resistance
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Best left to a mechanic
- Typical labour
- 0.5–3 h
- Emissions test
- Likely to fail
- After the fix
- A drive cycle is needed before the light stays off
- Parts involved
- Intake Air O2 Sensor B1, Intake Air O2 Sensor Heater B1, Wiring Harness, Ecm
Related codes
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.