Anti-Theft; Principles Of Operation; Encoded Ignition Key; Transceiver Module - Ford 2002 Bantam Workshop Manual

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419-01B-3
DIAGNOSIS AND TESTING

Anti-Theft

Principles of Operation

The passive anti-theft system (PATS) uses radio
frequency identification technology to deter a
drive away theft. Passive means that it does not
require any activity from the user.
With this PATS system:
• No master key is required.
• VIN data is stored within the powertrain
control module (PCM).
• Has fleet customer features.
• Spare key learning and erasing is possible.
CAUTION: There are two different types
of encoded PATS keys. One with a red
tag on the key, the other with a blue tag.
The PATS keys for this vehicle must
have a red tag or damage may be caused
to the control module when used.

Encoded Ignition Key

The PATS uses a specially encoded ignition key.
Each encoded ignition key contains a
permanently installed electronic device called a
transponder. Each transponder contains a unique
electronic identification code from millions of
combinations. Each encoded ignition key must be
programmed into the vehicles PATS Control
Function within the Powertrain Control Module
(PCM) before it can be used to start the engine.
There are special diagnostic repair procedures
outlined in this manual that must be carried out if
an encoded ignition key needs to be changed.
The PATS keys have a red transponder within
the head of the key. Only Ford approved ignition
keys should be used as some aftermarket
encoded ignition keys not purchased from a Ford
approved source may fail to operate especially at
high or low temperatures. A minimum of 2
encoded ignition keys must be programmed to a
vehicle in order for the engine to start. A
maximum of 8 ignition keys can be programmed
to a vehicle. The PATS control function within the
PCM will enter Anti-Scan Mode if a non-
programmed ignition key (with the correct
mechanical cut) is used to start the engine.
NOTE: If a non-programmed key has been used,
any further key reading is inhibited for 20
seconds. During these 20 seconds, no ignition
key will start the engine. To exit anti-scan mode
turn the ignition key to the position II and wait 30
E4861 EN
Anti-Theft — Passive
seconds, turn the ignition key to the position 0
and remove the key. Then turn the ignition key to
the position II with the correct programmed key.
PATS Control Function
The PATS control function is contained in the
PCM. This module carries out all of the PATS
functions, such as receiving the identification
code from the encoded ignition key and
controlling engine and starter enable. The PATS
control function initiates the key interrogation
sequence when the vehicle ignition switch is
turned to position II or position III.

Transceiver Module

The transceiver module communicates with the
encoded ignition key. This module is located on
the ignition key lock cylinder casting and contains
an antenna connected to a small electronics
module. During each vehicle start sequence, the
transceiver module reads the encoded ignition
key identification code and sends data to the
PATS control function within the PCM. No
configuration is required with the installation of a
new PATS transceiver.
Anti-Theft Indicator
The PATS system uses a visual anti-theft
indicator that is controlled by the PATS control
function. This indicator will self-test for three
seconds when the ignition switch is turned to
position II or position III under normal operation.
If there is a PATS problem, this indicator will
either flash rapidly or glow steadily when the
ignition switch is turned to position II or position
III and then it will flash a fault code 10 times.
Refer to the Diagnostic Trouble Code (DTC)
Index in this section or connect WDS and follow
the on-screen instructions. The PATS system
also flashes the anti-theft indicator every two
seconds at ignition 0 to act as a visual deterrent.
Starter Relay
The starter relay is also used as an additional
means of disabling the vehicle engine. The relay
is disabled when PATS cannot read an encoded
ignition key at ignition position II. However, the
system will not store a DTC or flash the anti-theft
indicator if a valid ignition key is read but a fault
occurs in the starter relay circuit.
Section 303-06. The relay is enabled when PATS
control function reads a valid encoded ignition
key at ignition II. The PATS will be activated and
will disable the vehicle from starting if there is a:
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07/2001 2002 Bantam