Section 13-11B: Anti-Theft System, Passive 1996 Mustang Workshop Manual
DESCRIPTION AND OPERATION Procedure revision date: 05/18/2000
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Components
The vehicle protection system contains the following components:
passive anti-theft system module
THEFT indicator
transceiver electronics
powertrain control module (PCM) (12A650)
encoded ignition key
RH drive anti-theft alarm control mounting bracket (19A435)
LH drive anti-theft alarm control mounting bracket
multiplex communications network
data link connector
The passive vehicle protection system components function as follows:
Theft Indicator
The passive anti-theft vehicle protection system utilizes the same anti-theft indicator, located in the instrument cluster (10849) that the anti-theft alarm system (if equipped) uses. (Refer to Section 13-11A.)
The indicator provides system proveout and operating status to the customer or service technician.
The anti-theft alarm system uses the theft indicator when the ignition switch is turned OFF. The passive anti-theft vehicle protection system uses the theft indicator when the ignition switch is turned to RUN/START position. The passive vehicle protection system will activate the indicator signal as described under the following conditions when the ignition switch is turned to RUN/START position:
THEFT Indicator ON two seconds, then OFF
Key Code Received/Vehicle Enabled (Programmed key)
THEFT Indicator ON two seconds, then OFF one second, then ON continuously
Key Code Received/Vehicle Disabled (Assembly plant use only, less than two keys programmed)
THEFT Indicator ON two seconds, then flash for one minute, then flash diagnostic trouble code 16 ten times
Key Code Received/Vehicle Enabled or Disabled (No PCM Verification)
If vehicle starts, powertrain control module is not working with control module
If vehicle does not start, Multiplex Communications Network may need service
You will need to go to the Symptom Chart in this Section for diagnostic assistance to isolate any communication system.
THEFT Indicator flashes for one minute
No Key Code Received (Key damaged, Non-encoded key, Wiring or Transceiver concern)
THEFT Indicator flashes for 15 minutes
Key Code Received/Vehicle Disabled (Key not programmed). Refer to Key Initialization Procedure in Service Procedures.
Encoded Ignition Key
When the vehicle ignition switch is placed into either RUN or START, the control module initiates a key interrogation sequence. The control module starts an interrogation period by supplying both power and the carrier signal to the transceiver to energize the ignition key. After the energize period has expired, the key transmits its ID code to the transceiver module. This ignition key is much larger in size due to the electronics that are located in the head of the ignition key.
Transceiver
The transceiver module is used to interface the control module to the encoded ignition key. The transceiver sends a signal to power up the encoded key and receives the ignition key data signal and sends it to the control module.
Passive Anti-Theft System Module
The control module contains circuitry to interface to the vehicle electrical system, the transceiver module, the vehicle multiplex communications network and the vehicle theft indicator located in the instrument cluster. The control module uses a microprocessor to control the system functions. The control module microprocessor stores the ignition key codes in non-volatile memory. The control module can be diagnosed through the data link connector.
Powertrain Control Module (PCM)
The passive vehicle protection system utilizes the engine management capabilities of the powertrain control module to enable or disable the vehicle engine. The multiplex communications network is used to send and receive messages to and from the powertrain control module. At each engine start sequence, the powertrain control module allows fuel and spark until the engine is running.
Within one second after engine start, the powertrain control module must receive an enable signal or the engine is disabled before the vehicle can be moved.
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