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500 EFI FUEL SYSTEM
FUEL LINES
Quick Connect Removal/Installation
CAUTION
Verify fuel system has been depressurized before
performing this procedure.
Sportsman 500 EFI models use quick connect fuel lines.
Refer to the steps for fuel line removal / installation:
1. Thoroughly clean the connector. Place a shop towel
around the fuel line to catch any dripping fuel.
Squeeze the connector tabs together and push the
locking tab out.
2. Pull out on the fuel line for removal.
3. To install the line, verify the connector and nipple are
clean and free of debris.
4. Snap the fuel line back over the nipple, verify the
connector tabs snap back into place.
Squeeze Connector Tabs
4.38
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
ELECTRONIC CONTROL UNIT (ECU)
Operation Overview
The ECU is the brain or central processing computer of the
entire EFI fuel/ignition management system. During
operation, sensors continuously gather data which is
relayed through the wiring harness to input circuits within
the ECU. Signals to the ECU include: ignition (on/off),
crankshaft position and speed (RPM), throttle position,
engine coolant temperature, air temperature, intake
manifold air pressure and battery voltage.
The ECU compares the input signals to the programmed
maps in its memory and determines the appropriate fuel
and spark requirements for the immediate operating
conditions. The ECU then sends output signals to set the
injector duration and ignition timing.
During operation, the ECU continually performs a
diagnostic check of itself, each of the sensors, and system
performance. If a fault is detected, the ECU turns on the
Malfunction Indicator Light (MIL) (Check Engine Light) on
the speedometer and stores the fault code in its fault
memory. A technician can access the stored fault codes
manually using a "blink code" diagnosis flashed out
through the instrument cluster or using the Digital Wrench
Diagnostic Software. The ECU requires a minimum of 7.0
volts to operate. The memory in the ECU is operational the
moment the battery cables are connected. Depending on
the significance or severity of the fault, normal operation
may continue, or a "Fail-Safe" operation may be initiated.
In the event a "Fail-Safe" mode occurs, a base fueling
table is used to determine the injector pulse width. This
strategy will not compensate for engine temperature,
intake air temperature, or altitude change, but instead
operates based on the latest valid information taken from
those sensors.
ECU
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