Exhaust Gas Temperature Sensor 1 Circuit Low
The exhaust gas temperature sensor is reading lower than expected.
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What it means (plain English)
The computer thinks the temperature of the exhaust gases is too low, which might mean the sensor or the circuit is faulty.
What the computer is actually seeing
The Engine Control Module (ECM) expects exhaust gas temperatures (EGT) to be within a specific range, typically from 300°F to 1000°F (149°C to 538°C) depending on engine operating conditions. If it reads below a threshold (like 100°F or 37.8°C) for a certain amount of time, the code is triggered.
What a healthy reading looks like
Expected EGT values for normal operation should be between 300°F and 1000°F depending on load and RPM.
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 connector to the EGT sensor for signs of damage, corrosion, or loose connections. Repair or replace as needed.
- 22. Measure the resistance of the EGT sensor with a multimeter. It should typically be around 10-100 Ohms; if out of range, replace the sensor.
- 33. Check the exhaust system for leaks near the sensor location that could cause inaccurate readings; repair if found.
- 44. Use a scan tool to read the current EGT value during operation. If the value is below the expected range and the wiring is good, replace the EGT sensor.
- 55. Clear the code and run the engine to see if it returns. If it does not return, you are good. If it does return, further diagnose the ECM for issues.
Common causes
- Faulty EGT sensor
- Wiring issue in the sensor circuit
- Bad connector or corrosion
- ECM calibration issue
- Exhaust leaks affecting sensor readings
Typical repair cost
$$
Related codes
Frequently asked questions
Can I still drive the vehicle safely?
Yes, but keep an eye on performance and check for other warning lights.
Will this code come back after clearing it?
It might if the underlying issue isn't fixed; monitor the situation.
Why does this code trigger with another code?
Often because multiple sensors are involved in monitoring exhaust temperatures.
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