Circuit/System Description

WARNING: This page is about a different car, the 2019 GMC Savana 3500, 2019 GMC Savana 2500, 2019 Chevrolet Express 3500, and 2019 Chevrolet Express 2500. However, it is still accessible from the selected car via links, so may be relevant.

For an overview of the component/system, refer to: Exhaust Aftertreatment System Description

Component	Description
B136 Exhaust Particulate Matter Sensor	The sensor measures the particulate matter in the for m of soot in the exhaust.
K115 Reductant Control Module	The control module controls the heating and dosing of the reductant.

The actual sensor surface is only a few square millimeters in size. On the surface there are 2 microscopic comb-shaped electrodes with intertwined tines (electrical traces) to have the longest possible route of transitions from one to the other electrode. Soot is conductive, therefor e when soot deposits between the electrodes, electrical current can flow from one electrode to the other. The more soot deposits between the electrodes, the lower the resistance. To measure the resistance, voltage is applied to the electrodes. The voltage also generates an electrical field that attracts the soot. If the sensor surface is saturated, the sensor is electrically heated to burn off the soot.