Directed Electronics 556L Manual

P P r r o o d d u u c c t t D D e e s s c c r r i i p p t t i i o o n n
The 556L General Motors Passlock Interface Module is used when
installing remote start products in GM vehicles equipped with
Passlock I and Passlock II anti-theft systems. The 556L provides
easy interfacing while maintaining the integrity of the vehicle's
anti-theft system. The 556L interfaces with the Passlock systems
by providing the proper Resistance Code (R-Code) at the appropri-
ate time. The 556L will also provide, when necessary, a negative
signal to the bulb check wire. The 556L has no effect on the
Passlock system when the remote start is not in use. The factory
Passlock anti-theft system will remain fully functional.
I I M M P P O O R R T T A A N N T T ! ! Before beginning the installation, make
sure that you are connecting to the correct type of
Passlock system (either Passlock I,Passlock II or alter-
nate). You can determine which type of system is being
used by referencing the Vehicle Application Guide
section in this manual.
P P a a s s s s l l o o c c k k S S y y s s t t e e m m D D e e t t a a i i l l s s
The GM Passlock System is a key-based, fuel shutdown, anti-theft
system. The Passlock system requires that the key cylinder be
mechanically turned using a key. When the key cylinder is properly
turned, it generates the R-Code, which is sent to the Instrument
Panel Cluster (IPC) in Passlock I systems or the Body Control
Module (BCM) in Passlock II systems. The IPC and the BCM both
house the Passlock decoder, which then interprets the signal.
Unlike the Passkey system, Passlock must detect the correct R-Code
at the correct time. The Passlock I system uses a bulb check wire
to activate the IPC module. This wire is not present in the Passlock
II system. In the Passlock I system, the bulb check wire is
© 2005 Directed Electronics, Inc. Vista, CA
N556L 05-05
556L General Motors
Passlock Interface Module
switched to ground when the ignition switch is turned to the crank
position. This initiates a time window during which the IPC ana-
lyzes the R-Code. If the R-Code is valid and received in the proper
window of time, the IPC sends a code via data bus to the
Powertrain Control Module (PCM) to enable the fuel system. The
vehicle will then start and stay running. If the R-Code is incorrect,
the vehicle will start and run for a moment and then shut off.
Passlock II also uses an R-Code, but rather than going through the
IPC, the signal is sent directly to the BCM. The Passlock decoder,
built into the BCM, then interprets the signal.
H H a a r r n n e e s s s s 1 1
1 GREEN/BLACK
2 BLACK/WHITE
3 BLACK
4 PINK
5 BLUE
6 VIOLET
7 RED
H H a a r r n n e e s s s s 2 2
1 WHITE
2 YELLOW
3 WHITE/YELLOW
4 BLACK/YELLOW
I I M M P P O O R R T T A A N N T T ! ! See instructions for passlock system that
applies for harness 2.
P P a a s s s s l l o o c c k k I I W W i i r r i i n n g g D D i i a a g g r r a a m m
I I M M P P O O R R T T A A N N T T ! ! Do not attempt to use the 556L before
learning the Resistance Code. (See Learning the
Resistance Code section of this manual.)
(+) Starter (from vehicle)
Bulb check
Passlock ground input
(+) Ignition (from vehicle)
(-) Status (from remote start system)
(-) Starter (from remote start system)
(+) 12V (+ battery)
R-code
R-code
R-code in
R-code BCM
1 1