Circuit/System Description
WARNING: This page is about a different car, the 2007 GMC Sierra, 2007 GMC Cab & Chassis Sierra, 2007 Chevrolet Silverado, and 2007 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
The exhaust gas temperature (EGT) sensors 1 and 2 are variable resistors that measures the temperature of the exhaust at the inlet second outlet of the diesel particulate filter (DPF). The engine control module (ECM) supplies a bias 5-volt signal to the EGT signal circuit, and supplies a ground to the low reference circuit. When the EGT is cold, the sensor resistance is low. When the EGT temperature increases, the sensor resistance increases.