Polaris 2012 Sportsman Forest 500 International, Service Manual

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4.29
500 EFI FUEL SYSTEM
4
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
500 EFI TRACTOR SPEED CONTROL
System Operation Overview
Sportsman 500 EFI Tractor models are equipped with a speed control system from the factory. This system is designed
to meet various international safety standards.
The speed control system consists of:
• A. ECU
• B. Speed Sensor
• C. Air Control Body Assembly
• D. Solenoid Valve
The speed control system utilizes the ECU (A), Speed Sensor (B), Air Control Body (C), Solenoid Valve (D), and engine
vacuum from the throttle body to operate. At closed throttle, the solenoid valve (D) is remains normally closed and the
slide valve (E) in the air control body is closed. As the throttle opens and engine RPM increases, the increase in vacuum
opens the slide valve (E), allowing more air to be drawn into the engine. The speed sensor signal (B) is monitored by
the ECU. When the speed sensor signal rises over 40 Kph (25 Mph), the ECU triggers the solenoid valve (D) to open,
allowing atmospheric pressure on top of the slide diaphragm (F). This drops the slide valve (E) down to limit the amount
of air entering the engine. Once the vehicle speed drops below 37-40 Kph (23-25 Mph), the solenoid valve (D) closes
and the operation repeats. Should the vehicle speed reach 67 Kph (42 Mph), the ‘check engine’ light will illuminate on
the LCD gauge to indicate there is a problem with the system.

B
E
A
D
C
F
Carb Adapter
Cylinder Head
A
B
C
D
E
F
LH Rear Brake
AI
R
A
IR