The P1157 code in your 2022 Honda Fit indicates a problem with the primary (upstream) heated oxygen sensor circuit. This Honda-specific code signals an issue with the sensor that monitors exhaust gases before the catalytic converter.
Understanding Primary O2 Sensors
The primary (front) oxygen sensor provides critical feedback for fuel mixture control. It has a built-in heater to reach operating temperature quickly. P1157 indicates either the heater circuit or sensor signal has a fault.
Common Causes of P1157
- Failed O2 sensor
- Heater circuit open or shorted
- Wiring damage to sensor
- Connector corrosion
- ECU circuit failure
- Exhaust leaks affecting sensor
Symptoms of O2 Sensor Circuit Issues
- Check engine light on
- Poor fuel economy
- Rich or lean running
- Rough idle
- Failed emissions test
- Hesitation on acceleration
Fit Efficiency Implications
The Fit is known for excellent fuel economy. A faulty O2 sensor disrupts fuel mixture optimization, significantly affecting efficiency.