The P1131 code in your 2022 Ford F-150 indicates the upstream (pre-catalyst) heated oxygen sensor on bank 1 is not switching between rich and lean as expected. This Ford-specific code signals the sensor is stuck lean, affecting fuel mixture control.
Understanding O2 Sensor Switching
The upstream O2 sensor should continuously switch between rich (above 0.45V) and lean (below 0.45V) readings during normal operation. P1131 indicates the sensor is stuck in the lean range, which can indicate an actual lean condition or sensor failure.
Common Causes of P1131
- Vacuum leak causing lean condition
- Lazy or failed O2 sensor
- Exhaust leak before sensor
- Low fuel pressure
- MAF sensor issues
- Injector problems on bank 1
Symptoms of Sensor Not Switching
- Check engine light on
- Rough idle
- Poor fuel economy
- Hesitation during acceleration
- Possible engine knock (if lean)
- Failed emissions test
F-150 Bank 1 Location
On the F-150's V6 or V8, bank 1 is typically the passenger side (right) containing cylinder 1. The upstream sensor is in the exhaust manifold or downpipe before the catalytic converter.