<!-- from fixya rte -->Fix anti theft deterrent system - 2007 Suzuki XL7 AWD

Vehicle Theft Deterrent (VTD) Description and Operation
The vehicle theft deterrent (VTD) system functions are provided by the theft deterrent control module. When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, 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 control module. The theft deterrent control module then compares this value to a value stored in memory, learned key code. If the value is correct the theft deterrent control module sends a random generated number to the transponder, this is called a challenge. Both the transponder and the theft deterrent control module perform a calculation on the challenge, if the calculations match the theft deterrent control module sends the fuel continue password via the serial data circuit to the Engine control module (ECM). If either the transponders unique value or the calculation to the challenge is incorrect the theft deterrent control module will send the fuel disable password to the ECM via the serial data circuit. The components of the VTD system are as follows:
• Theft deterrent control module
• Engine control module (ECM)
• Ignition key (Transponder)
• Ignition lock cylinder
• Security indicator
Theft Deterrent Control Module
Vehicles with steering column mounted ignition switches have the exciter integral with the theft deterrent control module which is located within the steering column. Vehicles with instrument panel mounted ignition switches have exciter modules separate from the theft deterrent control module with the vehicle wiring harness connecting the two. The theft deterrent control module for vehicles with instrument panel mounted ignition switches is located within the instrument panel. The theft deterrent control module can learn up to ten keys (transponder values).
The theft deterrent control module uses the following inputs, battery voltage, ignition switched voltage and ground circuit. The theft deterrent control module uses the following outputs, password exchange with the ECM, fuel continue/disable via the serial data circuit.
When an ignition key is inserted into the ignition lock cylinder and the ignition is switched ON, 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 control module. The theft deterrent control module then compares this value to a value stored in memory, learned key code. If the value is correct the theft deterrent control module sends a random generated number to the transponder, this is called a challenge. Both the transponder and the theft deterrent control module perform a calculation on the challenge. The theft deterrent control module then performs one of the following functions:
• If both the transponder value and the calculation to the challenge are correct, the theft deterrent control module will send the fuel continue password to the ECM via the serial data circuit.
• If either the transponders unique value or the calculation to the challenge is incorrect the theft deterrent control module will send the fuel disable password to the ECM via the serial data circuit.
• If the theft deterrent control module is unable to measure the ignition key transponder value for one second due to a damaged or missing pellet or a damaged exciter, the theft deterrent control module will send the fuel disable password to the ECM via the serial data circuit.
Important: On some vehicles, If the VTD system is unable to read the ignition key transponder value after the vehicle has started, the VTD system will consider itself malfunctioning. The VTD system will enter a fail enable state and will command the security indicator to illuminate. When the VTD system is in a fail enable state the vehicle will NOT stall or stop running. If the VTD system is in a fail enable state when the ignition is switched OFF, the VTD system will remain fail enable until it is able to read a learned ignition key transponder value. When the VTD system is in a fail enable state the VTD system is NOT active and the vehicle will start. This feature is NOT available on all GM vehicle lines.

It's hard to get the SECURITY light to go off when you don't know how it works ! Replacing the PCM could cause you more problems too . If a replacement PCM is being installed it must be programmed (flashed) using the latest Techline programming procedures.
Having the vehicle check for DTC ' S - diagnostic trouble codes would be the first step.
DTC P1626 Theft Deterrent Fuel Enable Signal Lost
DTC P1630 Theft Deterrent Learn Mode Active
DTC P1631 Theft Deterrent Start Enable Signal Not Correct
DTC P1632 Theft Deterrent Fuel Disable Signal Received

This anti-theft system does not use a TDM - theft deterrent module . The instrument cluster is the controlling module . Look at a wiring diagram here
http://www.bbbind.com/free_tsb.html Enter vehicle info. year , make , model engine . Then under systems click on body & accessories , then in subsystem click on security / anti-theft . Click the search button , then on the blue link .You mite be able to do a by-pass if the contacts inside the key lock cylinder is the problem . You can check it with ohm meter . The key has a resistor pellet on the side , you can check the value with ohm meter , find the two wires under the dash at the steering column . Two white wires inside a yellow or orange sheathing . There are videos on youtube !

Without a key with anti-theft transponder inside your not starting anything . Your best bet call mobile lock smith . Anti-theft system ,software programmed into all module's involved in starting the vehicle .
The vehicle theft deterrent (VTD) system functions are provided by the theft deterrent control module. The VTD system prevents vehicle operation if a learned Passkey III (PK3) ignition key is not used to start the vehicle. Vehicles with steering column mounted ignition switches have the exciter integral with the theft deterrent control module which is located within the steering column. Vehicles with instrument panel mounted ignition switches have exciter modules separate from the theft deterrent control module with the vehicle wiring harness connecting the two. The PK3 key has a transponder embedded in the plastic head of the key. The exciter is an antenna which is made up of wire coils which surround the ignition lock cylinder. The PCM enables engine starting when it receives a learned fuel enable signal from the theft deterrent control module. The components of the VTD system are as follows:

Anti-theft system transceiver ?
Theft Deterrent System
The Theft Deterrent System on this vehicle is comprised of two separate systems, the Personal Automotive Security System (PASS-Key?® III) and the Content Theft Deterrent (CTD) system. These system are described and diagnosed separately within this section. For CTD operation, refer to Content Theft Deterrent (CTD) Description .
SECURITY Indicator The yellow indicator SECURITY on the instrument cluster is controlled by both the PASS-Key?® III system (VTD module) and the CTD system (RIM).
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PASS-Key?® III system, the VTD commands the instrument cluster to control the indicator only when the ignition switch is ON.

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CTD system, the RIM commands the instrument cluster to control the indicator only when the ignition switch is OFF.
PASS-Key?® III System The PASS-Key?® III system is designed to help prevent vehicle theft by disabling the engine unless an ignition key with a specific electrical value is used in the ignition lock cylinder. The PASS-Key?® III system operates independently of the CTD system. Protection is provided even if the CTD system is not armed. The components of the system are the ignition keys (black or gray), ignition lock cylinder, Theft Deterrent (VTD) module, Reader Exciter, Powertrain Control Module (PCM) and two starter relays (START 1 and 2) in the underhood fuse block.

Does it have anti-theft system ?
The vehicle theft deterrent system is designed in order to prevent vehicle theft by disabling the fuel injectors unless the lock cylinder is correctly engaged by a mechanical key. The theft deterrent system uses the following 4 components for theft prevention:
• The lock cylinder
• The ignition switch
• The body control module (BCM)
• The powertrain control module (PCM) Do you have a SECURITY light lit on the dash ?

Is that why you changed the ignition switch in the first place ? No crank - no start ? Did you check the park neutral switch ? Is there a theft light lit ? Theft deterrent relay ? You have to know how it works if you want to fix the problem . When you turn the key to start , the B+ power goes through the park neutral switch for automatic transmissions or the clutch start switch for manual transmissions , to the theft deterrent relay , to the theft deterrent module . If there is no anti-theft system problems the theft deterrent module energizes the relay ,closing the contacts inside sending B+ voltage to the S terminal on the starter solenoid . Go to www.bbbind.com/ for free wiring diagrams an check it out !

It's hard to fix something if you don't know how it works ! Fixed ignition ? What did you fix or change ?
SERVICE THEFT SYSTEM
Security: Refer to Theft Systems Description and Operation in Theft Deterrent
You need to have it checked for trouble codes .
The theft deterrent system on this vehicle is comprised of two separate systems, the vehicle theft deterrent (VTD) system and the content theft deterrent (CTD) system. The VTD system prevents drive away theft by keeping the vehicle from starting. The CTD system is the vehicle alarm system which discourages unauthorized entry into the vehicle. These systems are described and diagnosed separately within this section.
Theft System Indicators
SECURITY The instrument panel cluster (IPC) illuminates the SECURITY indicator as determined by the vehicle theft deterrent (VTD) system and the content theft deterrent (CTD) system. The IPC receives a message from the theft deterrent control module or the rear integration module (RIM) via the serial data circuit requesting illumination.
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The VTD system requests the IPC to illuminate the indicator only when the ignition switch is ON. The VTD system uses the indicator as a malfunction indicator. For specific VTD condition that will illuminate the security indicator, refer to Vehicle Theft Deterrent (VTD) Description and Operation .

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The CTD system requests the IPC to illuminate the indicator only when the ignition switch is OFF. The CTD system uses the indicator in order to identify system status. For specific CTD condition that will illuminate the security indicator, refer to Content Theft Deterrent (CTD) Description and Operation .

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The IPC performs the displays test at the start of each ignition cycle. The indicator illuminates for approximately 3 seconds.
SERVICE THEFT SYSTEM The radio illuminates the SERVICE THEFT SYSTEM message when the VTD system detects a failure. The radio receives a message from the theft deterrent control module via the serial data circuit requesting illumination.
This is one you need to take to the dealer , unless you have a GM factory scan tool !

Where is the ignition switch at , on the steering column ? Did you transfer the theft deterrent control module from the old column to the new one ? Do you have any lights lit on the dash , SECURITY ? Your car has a anti-theft system , the key has a transponder pellet imbedded in the head of it . Behind the plastic cover of the steering column ,around the ignition lock cylinder is the theft deterrent control module an antenna !
The vehicle theft deterrent (VTD) system functions are provided by the theft deterrent control module. The VTD system prevents vehicle operation if a valid (learned) transponder PASS-Key?®III (PK3) ignition key is not used to start the vehicle. The theft deterrent control module has an exciter that is part of the theft deterrent control module as an assembly. The PK3 key has a transponder embedded in the plastic head of the key. The exciter is an antenna which is made up of wire coils which surround the ignition lock cylinder. The PCM enables the engines starter and fuel delivery system when it receives a valid (learned) password from the theft deterrent control module via the class 2 serial data circuit. The components of the VTD system are as follows:

there is one wyre you can cut coming from the computer check itrenet taht will disable antitheft everything else will work properly that will let you no if it is the anti theft

Check the help links mentioned below :---Relearn Theft deterrent module? http://technoanswers.blogspot.com/2012/01/relearn-theft-deterrent-module.html
---------theft deterrent module Relearning? http://howtobyme.blogspot.com/2012/01/buick-theft-deterrent-module-relearning.html
--------Engine will not crank after relearning Theft deterrent module? http://howtobyme.blogspot.com/2012/01/engine-will-not-crank-after-relearning.html
--------Can car radio code block Passkey anti theft system ?

http://schematicsdiagram.blogspot.com/2011/12/can-car-radio-code-block-passkey-anti.html
Car Factory Alarm will go off? http://repairhelpcenter.blogspot.com/2012/01/toyota-avalon-factory-alarm-will-go-off.html
---------Car will not start security lock out? http://technoanswers.blogspot.com/2011/12/car-will-not-start-security-lock-out.html
---------Alarm will not disengage? http://technoanswers.blogspot.com/2012/01/ford-pickup-alarm-will-not-disengage.html
--------This will help.For more info keep updated.Thanks.