Powertrain
generic / SAE
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.
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / numberB / 89
Possible causes
- Signal wire shorted to ground high
- Internal sensor short medium
- Connector pins corroded - high contact resistance low
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: medium
- DIY: shop recommended
- Estimated cost: 150–800 €
- Estimated time: 0.5–3 h
- Component: intake air o2 sensor b1
- Component: intake air o2 sensor heater b1
- Component: wiring harness
- Component: ecm
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012