Electronic Control Unit (Ecu); Operation Overview; Ecu Service; Ecu Replacement - Polaris 2014 Sportsman 570 EF Service Manual

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.
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.
IMPORTANT: To prevent engine over-speed and
possible failure, an RPM
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
maximum.
Max RPM Limit: 7750 RPM
Idle RPM: 1200 ± 100 RPM
9924871 R03 - 2014 Polaris Sportsman® 570 EFI Service Manual

ECU Service

Never attempt to disassemble the ECU. It is sealed to
prevent damage to internal components. Warranty is void
if the case is opened or tampered with in any way.
All operating and control functions within the ECU are
pre-set. No internal servicing or readjustment may be
performed. If a problem is encountered, and you
determine the ECU to be faulty, contact the Polaris
Service Department for specific handling instructions. Do
not replace the ECU without factory authorization.
The relationship between the ECU and the throttle
position sensor (TPS) is very critical to proper system
operation. If the TPS is faulty, or the mounting position of
the TPS to the throttle body is altered, the TPS must be
adjusted.
For the purpose of troubleshooting, a known-good ECU
from another Polaris product of the same model may be
used without system or engine component damage.

ECU Replacement

Although the need for ECU replacement is unlikely, a
specific replacement procedure is required to ensure that
all essential data contained within the original ECU is
transferred to the replacement ECU.
NOTE: Refer to this procedure and carefully follow
all instructions provided in Digital Wrench .
1. Carefully follow the ECU replacement instructions
2. Remove the front cover (fastened to the front cab
limiting feature is
to the preset
3. Rotate the ecu towards the front of the vehicle and
© Copyright 2013 Polaris Sales Inc.
FUEL SYSTEM - GENERAL
provided in Digital Wrench to ensure that all
essential data contained within the original ECU is
transferred to the replacement ECU.
under the front rack). Remove the plastic push rivet
(1) that attaches the ECU to mount to the vehicle.
lift up to free the ecu mount from the vehicle.
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