Fault Phenomenon: Caterpillar 770G mining truck instrument displays abnormally high exhaust temperature, engine automatically reduces power, but actual temperature is normal.

Troubleshooting Process:
– Checked sensor: EGT sensor thermocouple aged or damaged.
– Checked wiring: line resistance increased or interference.
– Checked installation: insufficient sensor installation depth.
– Checked comparison: compare with infrared thermometer.

Root Cause: The exhaust temperature sensor thermocouple characteristics drifted due to long-term high-temperature exposure, outputting a higher signal and falsely triggering protection.

Required Parts: Replace exhaust temperature sensor.