Theory Of Operation

WARNING: This page is about a different variant/trim than selected.

There are four Exhaust Gas Temperature Sensors (#1, #2, Catalyst, and #3) used by the Powertrain Control Module (PCM) to monitor engine exhaust temperatures in the aftertreatment system. These 2-wire/5-Volt sensors are thermistors and change resistance based on the temperature being measured. When the exhaust gas temperature is cold, the sensor thermistor resistance is high. When the exhaust gas temperature is hot, the sensor thermistor resistance is low. The Catalyst Exhaust Gas Temperature Sensor is located between the Diesel Oxidation Catalyst (DOC) and the Diesel Particulate Filter (DPF). It sends a signal to the PCM indicating the temperature of the exhaust gases exiting the DOC and entering the DPF. This is a 2-trip fault. The PCM illuminates the MIL lamp immediately when the diagnostic runs and fails. The PCM also disables active regeneration mode. The PCM will turn off the MIL lamp after the diagnostic runs and passes on four consecutive drive cycles.