Exhaust Temperature Sensor 1 Circuit Low
The exhaust temperature sensor circuit is reading a low voltage signal.
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What it means (plain English)
The exhaust temperature sensor measures how hot your exhaust is. If it's too cold, it might mean the sensor is failing or there's a wiring issue. This reading should typically be between 0.5V and 4.5V depending on the temperature.
What the computer is actually seeing
The engine control module (ECM) expects a certain voltage range from the exhaust temperature sensor. If it sees a voltage lower than 0.2V or higher than 4.8V, it triggers this fault code.
What a healthy reading looks like
Expected voltage from the exhaust temperature sensor while the engine is running: approximately 0.5V (cold) to 4.5V (hot).
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. Check the exhaust temperature sensor wiring for damage or corrosion. Repair as needed. Proceed to step 2.
- 22. Inspect the connector for the exhaust temperature sensor for tightness and corrosion. Clean or replace as necessary. If good, proceed to step 3.
- 33. Measure the voltage at the sensor connector with the engine running. Expected value is 0.5V to 4.5V. If low, replace the sensor. If normal, proceed to step 4.
- 44. Check the ground circuit for the sensor. Use a multimeter to check for continuity to ground. If there's no continuity, repair the ground circuit. If okay, the ECM may need checking.
Common causes
- Faulty exhaust temperature sensor
- Wiring issues or short circuit in the sensor circuit
- Corroded or loose connectors on the exhaust temperature sensor
Typical repair cost
$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to fix this soon as it can affect emissions and vehicle performance.
Will this code come back after clearing?
If the issue isn't resolved, it will likely return.
Why does this code appear with others?
It often pairs with related sensor faults or wiring issues.
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