Section 06 ENGINE MANAGEMENT (SDI)
Subsection 01 (OVERVIEW)
Waking-up the Engine Management System pow-
ers the ECM, the fuel pump, the ignition coil, the
injectors, and the gauges.
The battery is required to supply current mainly to
the fuel pump to allow a fuel pressure buildup. An
easy way to acknowledge if the Engine Manage-
ment System is woken-up, verify if gauges are lit
up.
The capacitor has two functions. It is used to sta-
bilize battery voltage when voltage from the volt-
age regulator/rectifier is charging the small bat-
tery. It also gives the possibility to be able to start
the engine even if the battery is very low. In this
case, starting the engine may be more difficult and
will require the very complete stroke of the start-
ing rope.
The capacitor relay prevents the capacitor to be
connected to the battery when the engine is not
running to allow safe vehicle maintenance (discon-
nection and reconnection of the capacitor).
Electric Start Models
When the start/RER switch is activated, it wakes
up the EMS and power the starting system relay
(R1), the ECM, the fuel pump, the ignition coil,
the injectors, and the gauges. Then, if the cut-
off switch and the DESS switch are in position
to allow starting and start/RER switch is hold, the
starter solenoid relay is activated.
All Models
When engine reaches approximately 800 RPM,
the ECM activates the headlights and accessory
relay (R2).
ECM — GENERAL FUNCTIONS
Automatic Power Shut-Down
The ECM is equipped with an automatic power
shut-down.
This feature prevents the battery
from losing its charge if the tether cord cap is
left on the post when the engine is not running
for more then 30 seconds. The ECM will remain
offline until the electric starter or the rewind
starter is activated. The ECM will shut down all
outputs after 5 seconds when the tether cord cap
is removed.
Digitally Encoded Security
System (DESS)
The following components are specially designed
for this system: ECM, tether cord cap and DESS
post.
This system allows the engine to reach pulley en-
gagement speed only if a programmed tether cord
cap is installed on DESS post.
The tether cord cap contains a magnet and a ROM
chip. The magnet actually closes the reed switch
inside the post which is the equivalent of a me-
chanical ON/OFF switch. The chip has a unique
digital code.
NOTE: Actually, it is the memory of the ECM
which is programmed to recognize the digital
code of the tether cord cap. This is achieved with
the VCK (Vehicle Communication Kit) (P/N 529
035 981). Refer to their operation manual or help
system to program a tether cord cap.
529 035 981
The system is quite flexible. Up to 8 tether cord
caps may be programmed in the memory of the
ECM. They can also be erased individually.
NOTE: If desired, a tether cord cap can be used
on other vehicle equipped with the DESS. It only
needs to be programmed for that vehicle.
When starting the engine with a tether cord cap
on the post, the DESS is activated and will emit
audible signals:
– 2 short beeps indicate a working tether cord
cap. Vehicle can be driven.
– short repetitive beeps indicates a wrong tether
cord cap is being used or that something is de-
fective. Vehicle can not be driven.
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