The theft deterrent system is a function of the theft
deterrent module. When a ignition key is inserted into the ignition lock
cylinder, the theft deterrent module uses wire coils surrounding the ignition
lock cylinder to energizes a transponder pellet located within the plastic
portion of the ignition key. The transponder when energized transmits
a unique value by radio frequency back to the theft deterrent module.
The theft deterrent module which then validates this value against a value
stored in memory and performs one of the following functions:
| • | If the value does match the stored value the theft deterrent module
sends the correct password via a class 2 message to the PCM, and the PCM
enables fuel delivery to the engine by activating the fuel injectors and activates
the starter relay. |
| | Important: The theft deterrent module and PCM operate in conjunction with each
other to determine fuel enable. A password is exchanged between the theft
deterrent module and PCM when the theft deterrent module detects a valid key
value over the class 2 serial data line. When the PCM receives a password
the PCM validates the password against a password stored in memory and
performs one of the following functions:
|
| - | If the password matches the PCM enables fuel delivery, and activates
the starter relay. |
| - | If the password does not match the PCM disables fuel delivery,
and does not activate the starter relay and sets a DTC. |
| • | If the value does not match the stored value, the PCM disables
fuel delivery to the engine by disabling the fuel injectors, and does not
activate the vehicle starter relay . |
SECURITY Indicator Operation
The theft deterrent 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 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 illuminated and Engine Starts
If the indicator stays illuminated after the engine starts this indicates
that one of the following conditions has occurred:
| • | After the engine is running, the theft deterrent module measures
an invalid transponder value for 30 consecutive seconds. The theft deterrent
module may allow the engine to restart during this condition. |
| • | If the theft deterrent module detected a problem in the ignition
key transponder while the engine was last running the SECURITY indicator illuminates
until the problem is corrected. |
SECURITY Indicator Illuminates when Engine is Running
If the theft deterrent module is unable to measure the ignition key
transponder value or the PCM loses communication with the theft deterrent
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 stays Illuminated and Engine Does Not Start
The theft deterrent module measures an invalid transponder value when
the ignition key is turned to the ON position.
SECURITY indicator flashes and Engine Does Not Start
If the indicator flashes and the engine does not start, the theft deterrent
module has detected a problem with the theft deterrent system. During this
mode of operation the theft deterrent module does not start the system
disable interval.
