Engine Exhaust Temperature Sensor Circuit Low
The exhaust temperature sensor circuit is reporting low voltage.
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What it means (plain English)
The exhaust temperature sensor measures how hot the exhaust gases are. If it says it’s too cold, it’s like seeing a temperature reading of 0 degrees when it should be 500 degrees on a hot engine.
What the computer is actually seeing
The engine control module (ECM) sees a voltage signal from the exhaust temperature sensor that is below the expected range, typically less than 0.3 volts when it should be around 1 to 5 volts depending on the sensor's condition.
What a healthy reading looks like
Normal voltage for a functioning exhaust temperature sensor should be between 1V to 5V at operating temperature, with specific ranges depending on the vehicle make and model. Check your vehicle's specifications for exact values.
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 the wiring and connectors for the exhaust temperature sensor. Look for any signs of damage or corrosion.
- 22. Check the exhaust temperature sensor's resistance with a multimeter. It should show a resistance typically around 500 ohms to 5k ohms at room temperature.
- 33. With the engine running, measure the voltage at the exhaust temperature sensor connector. Ensure it’s within 1V to 5V range. If not, check wiring to ECM.
- 44. If the voltage is correct but the code persists, replace the exhaust temperature sensor and clear the code to see if it returns.
Common causes
- Faulty exhaust temperature sensor
- Wiring issues (open or shorted circuits)
- ECM software glitch
- Corroded or loose connectors
- Exhaust leaks near the sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It’s drivable, but keep an eye on engine performance and fuel economy, and fix the issue soon.
Will this code come back after clearing?
If the underlying issue isn't resolved, yes, the code is likely to return.
Why does this code pair with other SPN codes?
Multiple SPN codes can indicate related issues in the exhaust system or faulty sensors with linked circuits.
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