Theory of Operation

WARNING: This page is about a different car, the 2011 RAM Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.

The Inlet Air Pressure is part of the Inlet Temperature/Pressure Sensor which is located in the top of the air cleaner box. The Inlet Air Temperature Sensor performance looks at the outputs of four temperature sensors and compares them under cold start conditions. At key on after an eight hour cold soak, the values of the Inlet Air Temperature, Engine Coolant Temperature, Intake Air Temperature and EGR Orifice Temperature sensors are compared. If the Engine Coolant, Intake Air and EGR Orifice Temperature Sensors agree and the Inlet Air Temperature does not agree, the Inlet Air Temperature Sensor is declared irrational. This diagnostics also checks for a change in sensor value over a period of time. This is to verify that the sensor is responding with temperature change. The Powertrain Control Module (PCM) will illuminate the MIL lamp after this diagnostic runs and fails in two consecutive drive cycles. The PCM will turn off the MIL lamp once the diagnostic runs and passes in four consecutive drive cycles.