On DDEC III/IV engines there is an Air Temperature Sensor (ATS) mounted to the bottom of the intake manifold. The ATS sends an electrical signal to the ECM indicating the inlet manifold temperature of the air entering the engine. The ECM uses this information to adjust gas flow, control air fuel ratio and in some cases fan control. The ATS provides necessary input to vary hot idle speed and injection timing resulting in improved cold starts and reduced white smoke.
|1. Intake Manifold ||2. Air Intake Sensor|