Engine Exhaust Temperature Sensor 1, High
Indicates that the exhaust temperature is too high at sensor 1.
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What it means (plain English)
The engine has an exhaust temperature sensor that measures how hot the exhaust gases are. If it gets too hot, the sensor triggers a fault code to alert you.
What the computer is actually seeing
The engine control module (ECM) sees a voltage signal from the exhaust temperature sensor that exceeds the normal range, typically above 1.5 volts when it should be around 0.5-1.0 volts during normal operation.
What a healthy reading looks like
Expected voltage should be between 0.5 to 1.0 volts at temperature readings of around 300-700°F (149-371°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.
- 1Start by inspecting the exhaust temperature sensor wiring for any visible damage or frays.
- 2Check the connector pins for corrosion or loose connections.
- 3Verify the exhaust temperature sensor's resistance using a multimeter. At room temperature (around 70°F), it should read approximately 1.5k ohms. Replace if out of range.
- 4Start the engine and monitor the exhaust temperature sensor signal with a scan tool. It should fall between 0.5v and 1.0v during normal operation conditions. If not, the sensor may need replacement.
Common causes
- Faulty exhaust temperature sensor
- Short in sensor wiring
- Exhaust leaks near the sensor
- Defective ECM
- Bad connections at the sensor plug
Typical repair cost
$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It is not recommended to drive with this code as it may affect performance and emissions.
Will this problem come back after repairs?
If the underlying issue is not fixed, such as wiring or connection problems, the code may return.
Why does this code show up with other codes?
Multiple codes usually indicate related sensor or wiring issues in the exhaust system.
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