Powertrain
generic / SAE
P2272
O2 Sensor Signal Stuck Lean (Bank 2, Sensor 2)
The downstream oxygen sensor on bank 2 reports a constant lean signal during a forced-rich command from the ECU. Suggests either a sensor that has lost its rich-side response, or a catalyst that is so degraded that no rich exhaust reaches the downstream sensor (cross-check P0420).
SystemPowertrain
Typegeneric / SAE
GroupP2
Range / number2 / 72
Possible causes
- Downstream sensor failed stuck lean high
- Exhaust leak after catalyst medium
Symptoms
- Check engine light on
- Increased fuel consumption
- Possible rough idle or hesitation
- Failed emissions test
Inspection / repair
- Difficulty: medium
- DIY: possible
- Estimated cost: 60–800 €
- Estimated time: 0.3–4 h
- Component: oxygen sensor downstream
- Component: catalytic converter
- MIL / check engine light
- emissions-relevant
- drive cycle required
Sources
References
sae:J2012