Electronic Control Unit (Ecu); Operation Overview - Polaris RZR 570 2013 Service Manual

FUEL SYSTEM

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, intake air temperature, intake manifold absolute 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.
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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 "Check Engine" light in the speedometer and stores the fault
code in its fault memory. Depending on the significance or severity of the fault, normal operation may continue, or
"Fail-Safe" operation (slowed speed, richer running) may be initiated. A technician can determine the cause of the
"Check Engine" light by referencing the "Instrument Cluster Trouble Code Display" and "Diagnostic Trouble Code
Table" or by using Digital Wrench®. 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.
To prevent engine over-speed and possible failure, an RPM limiting feature is programmed into the ECU. If the
maximum RPM limit is exceeded, the ECU suppresses the injection signals, cutting off the fuel flow and retards the
ignition timing. This process repeats it self in rapid succession, limiting operation to the preset maximum.
RZR 570 EFI RPM Limit:
Max RPM Limit - Injector and ignition suppression.
• 7750 RPM (All Gears)
9926813 R04 - 2013-2016 RZR 570 Service Manual
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