Service theft system alarm comes on everytime I star my vehicle.

When the anti-theft system in your car is activated, it is designed to prevent unauthorized access to the vehicle and protect it from theft. The specific features and functions affected by the activation of the anti-theft system can vary depending on the make and model of your car. However, here are some common ways in which the anti-theft system can impact your vehicle:

1. Ignition Interlock: In many vehicles, the anti-theft system can prevent the engine from starting or cut off power to the ignition system. This is often the primary function of the anti-theft system to deter thieves from driving the vehicle.
2. Key Removal: Some anti-theft systems can also lock the key in the ignition switch, making it difficult or impossible to remove the key when the system is activated.
3. Door Locks: The anti-theft system may lock or unlock the doors automatically when it is activated. This can be intended to prevent unauthorized entry.
4. Windows and Sunroof: In some cases, the anti-theft system can disable the power windows and sunroof to prevent someone from gaining access to the interior through these openings.
5. Alarm Activation: If your vehicle is equipped with a security alarm system as part of the anti-theft system, it may activate the alarm if unauthorized entry is detected or if someone tries to tamper with the vehicle.
6. Vehicle Immobilization: Some advanced anti-theft systems can immobilize the vehicle by cutting off fuel or electrical power to the engine.

If you're experiencing issues with your key not coming out, windows not rolling down, and the sunroof not opening, it's possible that these problems are related to the activation or malfunction of the anti-theft system. However, it's essential to consult your vehicle's owner's manual or contact the manufacturer or a qualified automotive technician for specific information about how your vehicle's anti-theft system operates and to diagnose and resolve the issues you're facing.

In many cases, anti-theft system problems may require specialized equipment and knowledge to diagnose and repair, so seeking professional assistance is often the best course of action.

Dis arm the alarm with your key fob.

What alarm ? Content theft alarm ? Think's the vehicle is being broken into ? Something other then horn going off ? This is the factory alarm .

Content Theft Deterrent (CTD) System
The Content Theft Deterrent function provides the theft deterrent by sounding the horn and flashing the headlamps and the park lamps when there is an unauthorized vehicle entry or there is tampering detected.

Anti-theft system can keep vehicle from starting , Alarm is for vehicle content theft , open door without key alarm sounds (horns) ! PATS - passive anti theft system PATS enables and disables the engine from starting ,it will not cause the engine to die ! You have some other kind of problem ! If the vehicle engine doesn't turn over an red light on top of dash flashes fast ,then you have anti-theft system problem !
PATS differs from the perimeter anti-theft system in that PATS enables and disables the engine from starting. If equipped, the perimeter anti-theft system protects the perimeter of the vehicle (doors, hood and trunk) and sounds an alarm.

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 !

What alarm ? Anti-theft ?
The theft deterrent system on this vehicle is comprised of 2 separate systems, the Vehicle Theft Deterrent (VTD) System and the Content Theft Deterrent (CTD) System. The VTD prevents drive away theft by preventing the vehicle from starting. The CTD is the vehicle alarm system which discourages unauthorized entry into the vehicle. These systems are described and diagnosed separately within this section.
SECURITY Indicator
The SECURITY indicator on the instrument panel cluster (IPC) is controlled by the body control module (BCM) through the security indicator control circuit.
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The Vehicle Theft Deterrent (VTD) System contained in the BCM commands the instrument cluster to control the SECURITY indicator only when the ignition switch is ON. The VTD System uses the telltale as a malfunction indicator.

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The Content Theft Deterrent (CTD) System also contained in the BCM commands the instrument cluster to control the indicator only when the ignition switch is OFF. The CTD System uses the SECURITY indicator to identify system status.

It's software , a program inside the BCM ! An you can't just replace the BCM , it needs programming ! The dealer is the place to have that done ,most of the time ! If there is a SECRUITY light lit on the dash ,there is a DTC - diagnostic trouble code stored in the BCM , this code will point the service technician in the diagnostic path !

I don't know who told you that , a semi- clogged catalytic will cause a low power issue an maybe a couple of DTC'S diagnostic trouble codes P0420 - P0430 ,Has nothing to do with the alarm system ! Do you mean Service vehicle soon or SERVICE ENGINE SOON ?
SERVICE VEHICLE SOON
The IPC illuminates the SERVICE VEHICLE SOON indicator in the message center when the PCM or the BCM detects certain non-emissions related malfunctions. The IPC receives a class 2 message from the PCM or from the BCM requesting illumination. What problem are you having with alarm system ? If you have a starting issue it's the Anti-Theft system not alarm system . The alarm would go off if you vehicle was broke into . I don't know what shop you took it to but did you try a dealer ?

How to Diagnose Codes P0420 P0430

Operation of the theft deterrent system is discussed in the 1999 Toyota Camry Owner's Manual beginningh on page 21. Unlocking the door with the key should disarm the alarm system. If it does not disarm when using the key, there are only two possibilities:

> You have an aftermarket alarm system installed in addition to the system tht was provided by the manufacturer and they are interfering with each other.

> OR

> Your vehicle needs service to correct the malfunction.

You might try unlocking the car from the passenger side or use the key to open the trunk first to see if this works. If it does, the switch inside the driver door is probably malfunctioning.

It indicates there is a problem in one or more of the sensors for the anti theft (Vehicle Alarm) system or the alarm unit itself is malfunctioning.

Section 13-11: Anti-Theft System, Active 1998 Windstar Workshop Manual DESCRIPTION AND OPERATION Anti-Theft Alarm System NOTE: The system immediately monitors the ignition key lock cylinder upon removal of the key from the ignition. It is not necessary to arm the system for ignition key lock monitoring.

The anti-theft alarm system:

• protects the vehicle from unauthorized entry into the passenger compartment, engine compartment and cargo area.
• monitors the status of the ignition key lock cylinder.
• is controlled by a remote anti-theft personality (RAP) module. The remote anti-theft personality module also controls the electronic door lock functions. Refer to Section 01-14B for more details.
• when armed, detects unauthorized entry into the passenger compartment by using an input from the GEM module regarding the state of the door or liftgate (open or closed).
• protects the engine compartment with a hood switch which is located on the LH cowl vent panel and is part of windshield wiper motor wiring (17A477) .
• triggers an alarm if the ignition lock cylinder is forcibly removed from the steering column.

Once triggered, the system responds by:

• flashing the low beam headlamps, the parklamps, rear lamps and the alarm indicator warning light emitting diode (LED).
• sounding the horn (13832).
• disabling the starter circuit until the system is disarmed.

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Remote Anti-Theft Personality Module

• The remote anti-theft personality module is located behind the instrument panel (04320).
• It contains a radio receiver that receives the RF signal from the keyless entry remote transmitter (15K601) through the alarm and lock system antenna (15603) and sends the appropriate command to the power door locks, the horn relay, or the generic electronic module.
• The remote anti-theft personality module is equipped with an internal backup power supply which holds the programmed code in memory in the event the vehicle battery is disconnected.

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Remote Anti-Theft Personality Module Removal

1. Disconnect battery ground cable (14301). Refer to Section 14-01 .
   

1. Remove radio. Refer to Section 15-01 .
   

1. Remove lower instrument panel center finish panel. Refer to Section 01-12 .
   

1. Lower glove box.
   

1. Remove two remote anti-theft personality module bracket retaining screws.
   

1. Disconnect electrical connectors and alarm and lock system antenna (15603).
   

1. Remove remote anti-theft personality module and bracket.
   

1. Remove remote anti-theft personality module from mounting bracket.
   

Installation

1. To install, follow removal procedure in reverse order.
   

1. Tighten remote anti-theft personality module bracket retaining screws to 6-8 Nm (54-70 lb-in).
   
   

Components The system is composed of the following components:

• remote anti-theft personality (RAP) module with integral antenna
• alarm indicator LED
• door lock cylinder switch RH, door lock cylinder switch LH
• liftgate door lock cylinder switch (220A40)
• hood switch (part of windshield wiper motor wiring (17A477))
• ignition lock anti-theft switch (19A438)

The following vehicle components are also used by the anti-theft alarm system:

• generic electronic module
• power door lock switch (14028)
• door open warning lamp switch (14018)
• autolamp relay (14N089)
• horn relay and bracket (13853) and horn (13832)
• low beam headlamps
• rear lamps (13404) and parking lamps (13200)
• starter relay
• door lock relays
• keyless entry remote transmitter (15K601)

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Disarming an Untriggered System NOTE: A perimeter alarm will "shut off" after 165 seconds, but the system is still triggered and is not disarmed.

An armed but untriggered perimeter anti-theft system can be disarmed by one of the following four events:

1. Unlock the doors by pressing the keyless entry remote transmitter (15K601) UNLOCK button once.
2. Unlock any door with a key.
3. Turn ignition switch to RUN or ACC.
4. The remote entry PANIC button will disarm the anti-theft system only when the perimeter alarm is triggered and sounding.

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System Triggering NOTE: Although the remote entry PANIC alarm is not associated with the monitoring of the vehicle, the user will frequently say that the theft system was triggered when actually the keyless entry remote transmitter PANIC button was inadvertently pressed. A panic alarm will not flash the THEFT indicator.

The alarm can be triggered by the following events if the system has been armed and has not been disarmed first:

• Open any door or liftgate.
• Open the hood (16612) (if the hood was open when the system was armed, it must be closed before it can trigger the alarm).
• Dislodge the ignition key lock cylinder.
• The anti-theft system may be triggered inadvertently when the module is disconnected and then reconnected. To avoid inadvertent alarm triggering, disconnect the smaller 22-way connector first.

When the system is triggered the perimeter alarm will operate as follows: The remote anti-theft personality module will pulse the following outputs at approximately 1.3 Hz, 50 percent duty cycle for two minutes 45 seconds for North America. NOTE: Other perimeter alarms can be programmed for the system.

• low beam headlamps
• parking lamps
• horn
• THEFT indicator

The perimeter alarm can be retriggered, after a perimeter alarm has sounded for 165 seconds. After a perimeter alarm has timed out, if any trigger input is first seen as normal and is then seen in its trigger state, the perimeter alarm will be retriggered. The perimeter alarm can be triggered a total of three times between an arming sequence and a disarm event. An active panic alarm will be deactivated when a perimeter alarm is triggered (a perimeter alarm overrides a panic alarm).