Theory Of Operation
WARNING: This page is about a different car, the 2013 RAM 3500 HD and 2013 RAM 2500 HD. However, it is still accessible from the selected car via links, so may be relevant.
This diagnostic provides a continuous check of the O2 Sensor Heater circuit during operation. The heater circuit is momentarily disabled to allow a resistance measurement to be taken to calculate heater temperature. The current delivery to the heater is duty cycled to maintain a specific target temperature. The error from the target temperature is continuously monitored to determine heater performance.