OBD-II Code · Sensors
P2271
HO2S Signal Stuck Rich (Bank 1 Sensor 2)
low severitySafe to drive$150-$500
Downstream B1S2 stuck rich.
Common symptoms
- CEL
- Catalyst code may follow
Likely causes
- Failed sensor
- Coolant/oil contamination
- Failed catalyst
Where to start
- Try the cheapest cause first. Start by checking: failed sensor.
- Cost & scope. $150-$500
- If the code returns after the fix: escalate to a shop or scanner with live-data and freeze-frame. A code that re-sets means the underlying fault is still there.
Related codes
P0176Flex Fuel Composition Sensor CircuitP0177Flex Fuel Composition Sensor RangeP0178Flex Fuel Composition Sensor Low InputP0179Flex Fuel Composition Sensor High InputP0130O2 Sensor Circuit Malfunction (Bank 1 Sensor 1)P0131O2 Sensor Circuit Low Voltage (B1S1)P0132O2 Sensor Circuit High Voltage (B1S1)P0133O2 Sensor Slow Response (B1S1)
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