P0426
PowertrainCatalystmoderate severityCatalyst Temperature Sensor Range/Performance (Bank 1, Sensor 1)
What P0426 Means
The PCM detected the bank 1 catalyst temperature sensor reading is out of the expected range. This indicates the sensor value is implausible.
Symptoms
- Check engine light on
- Failed emissions test
- Erratic temperature data
Common Causes
- Faulty catalyst temperature sensor
- Wiring resistance or corrosion
- Poor connector contact
- Failed catalytic converter
Diagnostic Steps
- Scan and confirm P0426
- Review sensor live data
- Inspect wiring and connector
- Test sensor against known values
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