9-3 (9440) L4-2.0L Turbo (2007)
In order to quickly generate a signal after start the oxygen sensor must be preheated. In order to control the heating effect the grounding of the circuit is
pulse width modulated.
The control module estimates the exhaust gas temperature on the basis of load and engine speed. At high temperatures the preheating is disconnected to
avoid damaging the oxygen sensor.