9929375 R02 - 2016-2019
GENERAL
/
GENERAL 4
Service Manual
© Copyright Polaris Industries Inc.
11.43
ELECTRONIC CONTROL UNIT (ECU)
ECU OPERATION OVERVIEW
The ECU
q
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 power (on/off), intake air temperature, manifold
absolute pressure (load), engine coolant temperature,
crankshaft position and engine speed (RPM), throttle
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, 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.
RPM Limit:
8800
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 of the same model may be used
without system or engine component damage.
ECU REPLACEMENT
SERVICE VIDEO
A service video has been created
to help highlight this procedure.
To view the video, either:
• Scan the QR Code with a
mobile device
• From a computer, right click
and open link in a new
window.
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.
NOTICE
Refer to this procedure and carefully follow all
instructions provided in Digital Wrench®.
1. Carefully follow the ECU replacement instructions
provided in Digital Wrench® to ensure that all
essential data contained within the original ECU is
transferred to the replacement ECU.
2. Remove the black plastic cover by lifting up on the
tab.
