Conditions for Running the DTC

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.

The engine is operating.
The HO2S heater is commanded ON.
The HO2S sensing cell voltage is between 3.4-4.7 volts.
DTC P2239 and P2242 run continuously once the above condition has been met.