Theory of Operation
WARNING: This page is about a different car, the 2011 RAM Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The Turbocharger Speed Sensor is a variable reluctance speed sensor. It consists of a coil of wire and an iron core. The target on the turbocharger shaft is a ground flat surface in the center of the shaft. As the flat surface on the turbocharger shaft spins past the speed sensor, a signal is generated. The Powertrain Control Module (PCM) interprets this signal and converts it to a turbocharger speed reading. This monitor is a two trip fault. The MIL lamp will turn off once the diagnostic runs and passes in four consecutive drive cycles.