4
2 UNDERSTANDING
THE SEQUENT 24
SYSTEM
The SEQUENT 24 system main-
tains, in general, the philosophy of
the previous SEQUENT systems it
derives from; it nevertheless intro-
duces some changes and improve-
ments as regards installation and
operation, as well as some modifi-
cations in the components the BRC
installer already knows well.
2.1 SEQUENT 24 ECU
A detailed description of the ECU
would be beside the point of this
handbook. The main point is to
underscore that it is the operational
unit controlling the system. As the
previous ones it complies with the
automotive and EMC standards
and is tight. What distinguishes it
from the previous ones is the fully-
plastic case and the much more
compact dimensions advantaging
its installation on the vehicle. For
installation please carefully follow
the indications given for the stan-
dard Sequent and Sequent Fast
that are already familiar to the BRC
installers.
2.2 CHANGEOVER SWITCH
Although it is similar to the typical
two-position changeover switch
provided with a buzzer, already
used on Sequent and Sequent
Fast, the differences distinguishing
it from the previous ones are
nevertheless substantial. This new
changeover switch can be conside-
red like a small ECU: it is not only a
switch regulating the petrol-gas
changing over, but it actually com-
municates with the ECU and con-
trols the visualisation of the gas
level in the tank on the 4 green
LEDs.
2.2.1 C
HANGEOVER SWITCH IN
ITS PETROL POSITION
With the button of the changeover
switch in its petrol position, the
vehicle works in forced petrol mode
(as in all the previous systems).
The rectangular red LED lit informs
the user, while the gas level infor-
mation disappears, that is to say
the four level green LEDs are off.
2.2.2 C
HANGEOVER SWITCH IN
ITS
GAS
POSITION
In this position the vehicle starts up
on petrol – the level LEDs are the-
refore off – and, with the changeo-
ver conditions configured by the
programme attained (see chapter
3.1 for further information), automa-
tically changes over to GAS. The
user is informed by the rectangular
LED that first becomes orange and
then green (gas operation). Only
while running on gas the gas level
in the tank is visualised on the four
green LEDs.
2.2.3 E
RROR INFORMATION
As it has already been undersco-
red, this changeover switch is an
“intelligent” device communicating
with the ECU. When the communi-
cation fails, the two level central
green LEDs and the rectangular
orange LED blinking inform the
user of the malfunction.
In such conditions it is always pos-
sible to force the petrol operation
turning the switch in its petrol posi-
tion, as it is possible to run on gas
with the changeover switch in its
gas position, though losing the level
information.
In these cases it is recommended
to make a diagnosis and, if need
be, to repair/or replace the chan-
geover switch.
2.3 GENIUS FOR SEQUENT
24
The pressure reducer is like the
LPG GENIUS for SEQUENT, unlike
it is provided with a new water tem-
perature sensor, that is not compa-
tible with the ones of the previous
systems.
Pict. 1
ECU Sequent 24
Pict. 2
Changeover switch
