The P1155 code in your 2020 Lexus LC indicates a problem with the air/fuel ratio sensor heater circuit on bank 2. This Toyota/Lexus-specific code signals the heater that brings the sensor to operating temperature has a fault.
A/F Sensor Heater Function
The LC's V8 uses wide-band A/F sensors for precise fuel control. Each sensor has a heater element to reach operating temperature (600°F+) quickly. P1155 indicates the bank 2 heater circuit has failed.
Common Causes of P1155
- Heater element failure
- Heater circuit open or shorted
- Wiring damage
- Connector corrosion
- ECU driver circuit failure
- Fuse or relay problems
Symptoms of Heater Failure
- Check engine light on
- Delayed closed-loop operation
- Poor cold start fuel economy
- Rich running when cold
- May run normally when warmed up
- Failed emissions test
LC Premium Experience
The Lexus LC is a premium grand tourer where smooth operation is paramount. Sensor issues can affect the refined driving experience expected from this flagship coupe.