When an ignition key is inserted into the ignition lock
cylinder, the transponder embedded in the head of the key is energized by
the exciter coils surrounding the ignition lock cylinder. The energized transponder
transmits a signal that contains its unique value, which is received by the
theft deterrent controller module. The theft deterrent controller module
then compares this value to a value stored in memory and performs one of
the following functions:
| • | If the transponder value is correct, the theft deterrent controller
module sends a class 2 message containing the module's unique enable
password to the PCM. |
| • | If the transponder value is incorrect, the theft deterrent controller
module sends a class 2 message containing a disable password to the
PCM. |
| • | If the theft deterrent controller module is unable to measure
the ignition key transponder value for one second (due to a damaged or missing
pellet or a damaged exciter), it sends a class 2 message containing
a disable password to the PCM |
| | Important: If the PCM is unable to communicate with the theft deterrent controller
module (loss of class 2 state of health) after the vehicle has started, the
module will consider itself malfunctioning and enter a fail enable state
and illuminate the Security Indicator. The vehicle will not stall or stop
running. If the PCM is in a fail enable state when the ignition is turned
to OFF, it will remain "fail enabled" until the next time the
vehicle is started. If the PCM is "fail enabled" the theft deterrent
system is NOT active and the vehicle will start. The PCM will remain "fail
enabled" until class 2 communication with the theft deterrent
controller module is restored.
|
When the PCM receives a password from the theft deterrent controller
module, the PCM compares the password to a password stored in its memory (learned
password) and performs one of the following functions:
| • | If the PCM receives a correct system enable password, indicating
a learned theft deterrent controller module has read a valid transponder value,
fuel delivery is enabled. |
| • | If the PCM receives a system disable password, indicating a theft
deterrent controller module has read an invalid transponder value, fuel delivery
is disabled. |
| • | If the PCM receives an incorrect password, indicating a theft
deterrent controller module that has not been learned by the PCM, fuel delivery
is disabled. |
| • | If the PCM has no communication with the theft deterrent controller
module, fuel delivery is disabled. |
SECURITY Indicator Operation
The theft deterrent controller module can command the instrument cluster
to illuminate the SECURITY indicator only when the ignition key is in the
ON position. If the PCM loses communication with the theft deterrent controller
module, the instrument cluster will also detect the loss of communication
and will illuminate the SECURITY indicator. The SECURITY indicator can indicate
both malfunctions (Indicator on steady) and tamper (Indicator flashing --
indicating unauthorized operation). Under the following conditions the SECURITY
indicator may be commanded to illuminate.
SECURITY Indicator Stays Illuminated and Engine Starts
If the theft deterrent controller module was unable to measure the ignition
key transponder value or the PCM lost communication with the theft deterrent
controller module while the engine was last running, the indicator will remain
illuminated during subsequent ignition cycles. This is to remind the driver
that the vehicle theft deterrent system will not be functioning until the
problem is corrected. The vehicle is "fail enabled" and will
start.
SECURITY Indicator Illuminates when Engine is Running
If the theft deterrent controller module is unable to measure the ignition
key transponder value or the PCM loses communication with the theft deterrent
controller module while the engine is running, the indicator will be illuminated.
If the key is turned to OFF, the vehicle will be "fail enabled"
and will start if the condition still exists at the next attempt to start
the vehicle.
SECURITY Indicator Illuminated and Engine Does Not Start
The theft deterrent controller module or the PCM has detected a problem
with the theft deterrent system. The theft deterrent controller module is
unable to measure the ignition key transponder value. The System is in Learn
Mode, refer to
Programming Replacement Keys, Ignition Cylinder, or Powertrain Control Module
.
SECURITY Indicator Flashes and Engine Does Not Start
The theft deterrent controller module has measured an incorrect transponder
value when the ignition key is turned to the ON position. The transponder
has not been "learned" by the theft deterrent controller module.
This is considered a tamper condition by the theft deterrent controller module.
