Preheating, rear heated oxygen sensor (HO2S)
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2006 Volvo S80, 2005 Volvo S80, 2004 Volvo S80, 2003 Volvo S80, and 2002 Volvo S80. However, it is still accessible from the selected car via links, so may be relevant.
Checking that the heating circuit begins after dew point has been reached. The control module registers electrical faults in the front probe. The control module measures the resistance in the heater element so that the probe temperature (which is continuously compared with a temperature model) can then be calculated. A diagnostic trouble code (DTC) for a faulty signal is stored if the temperature in the probe is lower than a designated value in the temperature model.