Temperature sensor testing

A method of testing temperature sensors of refrigerated cargo spaces, comprising: installing a wireless temperature sensor in proximity of a cargo space temperature sensor of a refrigerated cargo space; receiving, at a data processing device, temperature data from both the cargo space temperature sensor and the wireless temperature sensor; calculating a temperature difference between the temperature measured by the cargo space temperature sensor and the wireless temperature sensor; and calibrating or replacing the cargo space temperature sensor if the temperature difference exceeds a threshold difference.