Electronic Control Unit (Ecu); Operation Overview; Ecu Service; Ecu Replacement - Polaris RANGER XP 900 2013 Manual

ELECTRONIC CONTROL UNIT (ECU)

OPERATION OVERVIEW

The ECU is the brain or central processing computer of
the entire EFI fuel and 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 power (on/off), intake air temperature, manifold
absolute pressure (load), engine coolant temperature,
crankshaft position and engine speed (RPM), throttle
pedal position and battery voltage. The ECU compares
the input signals to the programmed maps in its memory
and determines the appropriate fuel and ignition
requirements for the immediate operating conditions.
The ECU then sends output signals to set 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 on the instrument cluster 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,
maximum engine RPM is controlled by the interface
between the ECU and Electronic Throttle Control (ETC).
Engine Max Operating RPM: 7250
9924880 Rev 2- 1/10/2014 - 2013 / 2014 RANGER XP 900 - 2014 RANGER XP 900 / CREW 900 Service Manual
© Copyright Polaris Sales Inc.
FUEL SYSTEM - GENERAL

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.
For the purpose of troubleshooting, a known-good ECU
from another Polaris RANGER XP 900 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. Remove the passenger seat base.
2. Connect the Vehicle Interface Cable to the Digital
Wrench® diagnostic connector. Go to the Special
Tests menu and select ECU Replacement. Carefully
follow the ECU replacement instructions.
3. Remove the (4) T-25 Torx head screws retaining
ECU to center tray.
4
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