Circuit/System Description

WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The exhaust differential pressure sensor measures the pressure difference across the inlet and outlet of the diesel particulate filter (DPF). The pressure difference across the DPF increases as the captured particulates in the DPF increase. A diaphragm within the differential pressure sensor is displaced by the pressure changes that occur from particulate matter loading. The sensor translates this action into electrical resistance. The engine control module (ECM) supplies a 5V reference circuit and a ground on the low reference circuit. The differential pressure sensor provides a signal voltage to the ECM, relative to the back pressure as a function of exhaust flow, DPF temperature, and soot loading. The ECM converts the signal voltage input into a pressure value.