2012 Sportsman 400/500 and EFI Tractor Service Manual 9923412, Page 165Get this manual
500 EFI FUEL SYSTEM INTAKE AIR TEMPERATURE SENSOR (IAT)
Operation Overview
The intake air temperature sensor (IAT) is used to indicate charge air temperatures to the ECUMounted on the rear of the air box, the IAT sends varying voltage signal to the ECU in direct correlation to the ambient air temperatureThis signal is processed by the ECU and compared to the internal pre-programmed maps to determine the required fuel and ignition settings for the amount of engine load
IDLE AIR CONTROL (IAC)
General Information
The Idle Air Control (IAC) is used to stabilize the idle quality of the engine at cold start-up and after warm-up operationsMounted on the throttle body, the IAC contains stepper motor which receives varying voltage signal pulses from the ECUThese pulses determine the IAC plunger setting, thereby controlling the amount of air bypassing the closed throttle body for idle controlIf the IAC is disconnected or inoperative, it will remain at it's last operated position
Intake Air Temperature Sensor Test
The IAT sensor is non-serviceable itemIf it is faulty, it must be replacedIt can be tested using the following method: With the test leads connected and the meter set to the ohms scale, observe the reading at room temperature (20C, 68F) The reading should be: