Hella KGaA Hueck & Co. 009768T Manuel D’Utilisation
2
Sep
te
mbe
r 12
, 2008
o
n
fiden
ti
a
l.
T
he con
tent
s
may
on
ly
be pa
ssed on
, u
s
ed
o
r
made
know
n
w
ith
ou
r e
x
pr
e
ss pe
rm
is
s
io
n
. All
ri
g
h
ts
re
se
rv
ed.
2
Hella PEPS for GM
Functional Description of Passive Start
PEPS ECU
3 interior LF antennas
UID
Start:
A
Person with the UID insid
e of the vehicle is
pressing the Start-Stop-Switch. The Start-
Stop-Switch activates the complete Passive
Start protocol:
The interior antenna IN is transmitting the LF
Data and a carrier si
gnal, which can be
recognized and evaluate
d by
quantity
(RSSI-
measurement) by
the UID. The other two
in
terior anten
n
a
s IN and
TRUNK tran
smit two
additional carrier signals sequential.
If the magnetic field strength of one of these
transmits is high enough (a certain border is
reached) then the UID authenticates the
sy
stem to start th
e veh
icle.
If the magnetic field strength of all antenna
tran
smits are too
low (th
e field streng
th
border is not reached, may
be the UID is
lay
ing outside or is held 10 cm outside the
vehicle) the car won’t start.
in
s
ide
de
tec
tio
n
trunk
se
pa
ra
ti
o
n