Exhaust Gas Temperature Sensor 2 High
The exhaust gas temperature sensor 2 has detected a higher-than-expected temperature.
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What it means (plain English)
The computer is seeing temperatures from sensor 2 that exceed the normal range, which can indicate a potential exhaust issue or sensor failure.
What the computer is actually seeing
The ECM monitors the temperature readings from exhaust gas temperature (EGT) sensor 2. When the reading exceeds the preset limit (typically over 1,000°F), it triggers the fault code SPN 3740.
What a healthy reading looks like
Expected EGT values typically range between 400°F and 850°F under normal operation for a diesel engine; values above 1,100°F can trigger issues.
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 wiring and connectors for exhaust gas temperature sensor 2 for any damage or corrosion. Fix any issues found.
- 22. Measure the resistance of the sensor. It should typically be around 5-10 ohms at room temperature. If not, replace the sensor.
- 33. Review the exhaust system for leaks or other components that could cause high temperatures, including turbocharger issues or burned-out gaskets.
- 44. Inspect and ensure that the exhaust gas temperature readings are within the specified expected values during operation.
- 55. Use a scanner to clear the code and perform a test drive. If the code returns, recheck sensor data and exhaust system for faults.
Common causes
- Failed exhaust gas temperature sensor 2
- Exhaust leaks causing erratic readings
- Short circuits or open circuits in sensor wiring
- Faulty ECM calculations due to other sensor faults
- Damaged exhaust components leading to unusual temperature spikes
Typical repair cost
$$-$$$
Related codes
Frequently asked questions
Is it safe to drive with this code?
It's best to address this fault soon; driving with it could increase exhaust temperatures and lead to further damage.
Will this code come back after clearing it?
If the underlying issue isn't fixed, yes, the code will likely return after a short drive.
Why does this code pair with other sensor codes?
Multiple sensor codes can occur if a common issue affects multiple sensors or if the exhaust system has more than one fault.
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