freightliner CENTURY CLASS S Driver Manual page 56

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07/01/96
1. System Status LED
2. Overhead Panel
Fig. 3.10, Red System-Status LED
10/09/98
Fig. 3.11, Program Switch
B-pillar electrical compartment door, that moni-
tors all the entry points, controls the door
locks, operates the alarm, and interrupts the
power to the engine, as necessary. There is
also a PDM (power distribution module) relay
module mounted on top of the left-hand side of
the ECM.
f541288
3. Clock
f541501a
How It Works
The fob has three push buttons: LOCK, UNLOCK,
and ALERT. When a button is pushed, the fob sends
a radio frequency signal to the ECM. The signal con-
tains a unique vehicle access code that identifies the
individual fob, plus codes that indicate which button
has been pushed.
The ECM detects the signal sent by the fob, ampli-
fies it, and converts it to a digital sequence.
If the LOCK button is pressed, the ECM arms the
system. It locks the two cab doors, begins to monitor
all the entry points (the two cab doors, the sleeper
cab access door, and the two baggage doors, as in-
stalled), and instructs the relay module to start flash-
ing the system LED at the slow rate. If any entry
points are open, the ECM sounds the horn and
flashes the cab marker lights twice. If the ignition
keyswitch is turned off, the ECM interrupts ignition
power to the engine.
The driver may be inside or outside the vehicle.
However, if the engine is running at the time the
LOCK button is pressed, the system still enters the
armed state, except that the engine is not immobi-
lized. This improves security for the occupant as well
as comfort while sleeping or resting, because the
system is armed, and the heating or air conditioning
is operating without draining any batteries.
Once the system is armed, the alarm functions acti-
vate whenever one of the entry points is opened. In
the alarmed state, the ECM does the following:
•
Immobilizes the vehicle by cutting off power
between the ignition keyswitch and the engine
electronic control unit (ECU).
•
Sounds the horn in pulses of 0.5 second on,
0.5 second off.
•
Flashes the cab marker lights in pulses of 0.5
second on, 0.5 second off.
•
Changes the blink rate of the LED from slow to
fast.
If the UNLOCK button is pressed, the ECM disarms
the system, if armed. It unlocks all the entry points,
discontinues its monitoring of the entry points, in-
structs the relay module to stop flashing the system
LED, and restores ignition power to the engine, if in-
terrupted.
Vehicle Access
3.8