When Monitored

WARNING: This page is about a different car, the 2016 RAM 3500 HD and 2016 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.

This diagnostic runs when the following conditions are met:

Battery voltage between 11.0 volts and 15.8 volts.
Engine coolant temperature at start up and Ambient temperature are greater than 7°C (45°F).
The difference between coolant temperature at engine start and ambient temperature are greater than 9°C (48°F).
The O2 Sensor heater temperature is greater than 401°C (754°F).