Common Symptoms
- Check Engine Light illuminated
- Reduced fuel economy
- Slight loss of power under acceleration
- Failed emissions test
- No noticeable drivability issues in some cases
Most Likely Root Causes
- Faulty or degraded catalytic converter
- Failed catalyst temperature sensor
- Exhaust leaks upstream of catalyst
- Engine running too cool due to stuck-open thermostat
- Fuel system issues causing rich or lean condition
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Component Location
The catalyst temperature sensor is located in or near the catalytic converter on bank 1 exhaust manifold side.
Manufacturer Notes
Some manufacturers use this code to monitor catalyst efficiency through temperature differential rather than oxygen sensor switching.
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