Code 73, High A/C Temperature: Notes

A/C temperature sensor is mounted to the evaporator which is located within the instrument panel. The PCM receives a voltage signal inversely proportional to the temperature at the evaporator coils. As the evaporator temperature increases or decreases, the resistance of the sensor changes and varies the voltage signal to the PCM. This voltage is converted to a temperature value by the PCM and can then be displayed in degrees on a scan tester. A Code 73 fault will be stored in the PCM when evaporator temperature is greater than 31°C but will not illuminate the SERVICE ENGINE SOON light.

NOTE: Test numbers refer to numbers on diagnostic chart.

Code 73 will set if A/C evaporator temperature sensor indicates greater than 31°C and time since start is 5 seconds or more.