The P1132 code in your 2021 Ford Explorer indicates the downstream (post-catalyst) heated oxygen sensor on bank 1 is not switching as expected. This Ford-specific code signals the catalyst monitoring sensor may be failing or the catalytic converter may have issues.
Downstream Sensor Function
The downstream O2 sensor monitors catalytic converter efficiency. Unlike upstream sensors that fluctuate rapidly, downstream sensors should show relatively stable readings with occasional switching. P1132 indicates abnormal switching patterns.
Common Causes of P1132
- Downstream O2 sensor failure
- Catalytic converter efficiency issues
- Exhaust leak after catalyst
- Sensor wiring problems
- Engine running rich affecting catalyst
- Sensor contamination
Symptoms of P1132
- Check engine light on
- Failed emissions test
- Usually no drivability symptoms
- May accompany P0420 catalyst code
- Slight fuel economy decrease
- Possible sulfur smell
Explorer Catalyst Monitoring
The Explorer's PCM uses the downstream sensor to verify catalyst operation. P1132 can indicate the sensor can't provide accurate catalyst efficiency data.