Catalyst Temperature Sensor 1/2 Correlation (Bank 1)
This code means the PCM/ECM has detected a correlation mismatch between related signals affecting catalyst temperature sensor 1/2. This can keep the emissions system from working correctly, which may raise tailpipe emissions, reduce fuel economy, and prevent readiness monitors from completing.
What You Might Notice
- Check Engine Light illuminated
- Reduced fuel economy
- Failed emissions or readiness monitor
- Rough idle or hesitation
- Possible exhaust smell or smoke
Most Common Causes
- 1
Aging or damaged catalytic converter
- 2
Oxygen sensor fault affecting catalyst monitoring
- 3
Exhaust leak ahead of the catalyst
- 4
Rich/lean running condition that overheats the catalyst
- 5
Engine misfire damaging the converter
How to Diagnose It
- 1
Check Aging or damaged catalytic converter — Inspect for signs of failure and test before replacing.
- 2
Check Oxygen sensor fault affecting catalyst monitoring — Inspect for signs of failure and test before replacing.
- 3
Check Exhaust leak ahead of the catalyst — Inspect for signs of failure and test before replacing.
- 4
Check Rich/lean running condition that overheats the catalyst — Inspect for signs of failure and test before replacing.
- 5
Check Engine misfire damaging the converter — Inspect for signs of failure and test before replacing.
How to Fix It
- 1
Inspect the sensor, valve, heater, and related hoses or pipes
- 2
Repair wiring or connector damage
- 3
Clean carbon buildup or repair leaks/restrictions
- 4
Replace the failed emissions component if testing confirms it
- 5
Clear the code and run the monitor to verify the fix
Need a deeper diagnosis?
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