Fault Phenomenon: Volvo L120 wheel loader instrument displays high transmission oil temperature alarm, but touching the transmission housing shows normal temperature.

Troubleshooting Process:
– Checked sensor: internal resistance drift or open circuit.
– Checked wiring: wiring shorted to ground or poor contact.
– Checked instrument: display module faulty.
– Checked actual temperature: compare with infrared thermometer.

Root Cause: The transmission oil temperature sensor failed, sending an erroneous high-temperature signal to the ECU, triggering false protection.

Required Parts: Replace transmission oil temperature sensor.