HO2S Heater Control Circuit High Bank 2 Sensor 3
Heater control voltage of bank 2 sensor 3 above the expected range. The sensor heater warms the element to operating temperature (~600 °C); without it the lambda sensor stays inactive in closed loop and the ECM cannot trim mixture.
Affected components
- Oxygen sensor b2s3 heater
- Heater wiring
Common causes
- High likelihood: Heater wiring shorted to battery
- Low likelihood: Connector pins corroded - high contact resistance
- Low likelihood: Supply wire pinched against B+ source
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.