Catalyst Temperature Sensor 1
Fault in the catalyst temperature sensor circuit.
Heads up: this code wasn't in our hand-written library yet, so DiagCoach AI built this page on the fly. Double-check critical specs against service info before condemning parts.
What it means (plain English)
The computer is reading an incorrect temperature from the catalytic converter's sensor, which can lead to poor emissions control and engine performance.
What the computer is actually seeing
The ECM gets a temperature signal from the catalyst temperature sensor that's outside its set parameters, usually below 0.5V or above 4.5V, indicating a malfunction.
What a healthy reading looks like
The temperature sensor should output between 0.5V (approx. 100°C) to 4.5V (approx. 900°C).
Guided diagnostic — the DiagCoach way
Don't just throw parts at it. Walk through these in order — each step tells you whether to keep going or stop and fix what you found.
- 11. Inspect wiring and connectors to the catalyst temperature sensor for damage or corrosion. Decision: Repair any issues found?
- 22. Check the temperature sensor's voltage output at the connector with the engine running. Decision: Is the voltage within 0.5V to 4.5V?
- 33. If the voltage is out of range, replace the sensor. Decision: Did the code clear after replacement?
- 44. If the voltage is within range, check for exhaust leaks or replace the wiring harness if damaged.
Common causes
- Damaged or corroded wiring to the sensor
- Faulty catalyst temperature sensor
- Connector issues
- Exhaust leaks near the sensor
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code present?
It's best to fix it soon, as it can affect emissions and may cause performance issues.
Will the code come back after being cleared?
If the issue isn't resolved, it will likely reappear.
Why does this code sometimes pair with other codes?
Other codes may indicate related problems in the exhaust or emissions system.
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