Theft light flashes without key in ignition

Your vehicle has two theft systems - content theft , if the door is opened without the key or keyless entry key fob the horn honks lights flash . PATS - passive anti-theft system ,this keeps the vehicle from starting if the computers don't see the right code from the transponder pellet in the head of the key .
You can turn off the content theft but not the PATS , when trying to start the vehicle does the theft light flash fast ? Red light on top of the dash .

the transponder has failed just under key cylinder a go test would be try another key and leave the ignition on without trying to crank it for 5 minutes then attempt if light starts flashing then anti theft is engaged .

When the light is flashing, the theft system is armed and immobilizing the car. Try leaving the ignition key in the on position for 10 minutes. See if the light stops blinking and goes off-if it does, the system is reset. Turn key to off and then try to start it.

If you are dealing with the anti theft the anti theft will flash as you are trying to start the vehicle if this is the case then it is the anti theft if not then you are not dealing with a ant theft issue. You can do a 30 minute relearn procedure without a scan tool. here is how Turn ignition on without the engine reunning.attempt to start the vehicle then release the key to ON.(vehicle doest start) Observe the security light.afeter 10 minutes the security light will turn off.Turn off the ignition and wait 5 seconds.do this 3 times for 30 minutes. start the engine with the engine started the vehicle will learn the passlock key.

ANTI-THEFT SYSTEM Passive anti-theft system
Your ignition key has a unique imbedded transponder which engages engine electronics and allows the vehicle to be started. Without the use of your special ignition key, the vehicle will not start.

During each vehicle start, the coded key is read by the anti-theft system. If the key’s ID code matches the code in the anti-theft system, the vehicle is enabled to start.

Anti-theft system
Briefly illuminates when the ignition is turned to the ON position to verify that the passive anti-theft system is operating properly.

Also, its possisble that tou have actovated the fuel pump switch.

CHeck it.

disconnect the battery for 3 mins

The theft light will only blink rapidly while cranking if the immobilizer inside the ignition switch isn't reading the CHIP inside the key. the immobilizer is part of the factory antitheft system. they don't normally go bad, but the key could have lost its programming. or if you had a copy made with just a metal key without the chip in it. the dealership can reprogram it for you if that is the problem.

the light blinks when the system is armed. Normal.

Your key has to be able to communicate with the receiver in the ignition area. Does your other key work ok?

Anti-Theft The passive anti-theft system (PATS) uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user.

• During each vehicle start sequence, the ignition key identification code is requested by the PATS module.
• If the key's ID code has been programmed into the system, the vehicle powertrain control module (PCM) (12A650) is allowed to operate; this allows the vehicle to start.
• If the key's ID code is not programmed into the PATS module, or if no encoded key is detected, then the vehicle PCM is disabled.

The PATS module, located under the driver side instrument panel, communicates the state of the security system to the PCM via the module communications network. The PCM, based on the communications from the PATS module, will determine if the vehicle's engine will be enabled to start. If the PCM prevents the vehicle from starting because of PATS, the PCM will store a DTC in memory.
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The anti-theft vehicle protection system utilizes the THEFT indicator, located in the instrument cluster (10849), when the ignition switch is turned to the RUN/START position. The indicator provides system prove out and operating status to the customer or technician.
Each PATS ignition key holds electronics that give each key a unique ID code.
The PATS will activate the indicator signal when the ignition switch is turned to the RUN/START position. The THEFT indicator will turn ON for two seconds, then turn OFF.
If the THEFT indicator flashes for one minute or more, this indicates that there was no key code received.
When the vehicle ignition switch is placed in either RUN or START, the PATS module requests the ignition key ID code. The PATS module requests the ignition key ID code by supplying power, ground, and the carrier signal to the transceiver to energize the ignition key. After the energize period, the key transmits its ID code to the transceiver module, which sends it to the PATS module.
The PATS module then compares the received KEY ID code to those stored in memory (16 maximum). If the ID matches, the PATS module sends an enable signal to the PCM over the module communication network.
The passive vehicle protection system utilizes the engine management capabilities of the PCM to enable or disable the vehicle engine. The module communication network is used to send and receive messages to and from the PCM.
Within one second after engine start, the PCM must receive an enable signal from the PATS module through the module communication network or the engine is disabled before the vehicle can be moved.
If the PATS module recognizes a stored ignition key code but there is a module communication network concern preventing the PCM from recognizing the start enable signal from the PATS module, the vehicle engine will be disabled. If this happens, the PATS module will flash the THEFT indicator for one minute, then flash diagnostic trouble code 16 ten times to indicate there is a problem with the module communication network circuits or the PCM is not responding properly.
The passive vehicle protection system will disable the vehicle from starting if there is a:

• Damaged encoded key.
• Unprogrammed key.
• Non-encoded key (key has no electronics).
• Wiring concern.
• Transceiver concern.
• Control module concern.
• Module communications network concern.
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Key Programming —Spare Key NOTE: Before starting this procedure, make sure the key(s) you want to program have the correct mechanical cut.
NOTE: Performing this procedure does not erase existing programmed keys.

1. Insert the programmed key in the ignition. Turn to RUN.

1. THEFT indicator proves out after two seconds.

1. Remove the programmed key.

1. Within 15 seconds, insert the new key in the ignition and turn to RUN.

1. THEFT indicator proves out after two seconds.

1. The extra key is now programmed.

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Key Programming —New Key (Without Diagnostic Tool) NOTE: Before starting this procedure, make sure the key(s) you want to program have the correct mechanical cut.

1. Insert the nonprogrammed key in the ignition and turn to RUN.

1. THEFT indicator flashes rapidly.

1. After 15 minutes of flashing, the THEFT indicator will stop flashing.

1. Within five minutes after the THEFT indicator has stopped flashing, turn the ignition key to OFF and back to RUN.

1. After 15 minutes of flashing, the THEFT indicator will stop flashing.

1. Within five minutes after the THEFT indicator has stopped flashing, turn the ignition key to OFF and back to RUN.

1. After 15 minutes of flashing, the THEFT indicator will stop flashing.

1. All originally programmed keys are now erased, and only the key in the ignition is programmed.

1. Additional keys may be programmed; refer to Key Programming—Spare Key .

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The ignition lock anti-theft switch (19A438) detects if the ignition key cylinder is broken or "slam pulled" during a theft. The ignition lock anti-theft switch is always monitored by the remote anti-theft personality (RAP) module. This allows the alarm system to be triggered in the case that the ignition lock anti-theft switch detects tampering of the ignition key cylinder (even in the event that the alarm is not active at the time).
Refer to the Section 501-14B for more details on the keyless entry remote transmitter (15K601).
The door open warning lamp switch (14018) communicates to the RAP module through the generic electronic module (GEM). This input to the RAP will cause the anti-theft alarm to be sounded if the anti-theft alarm was armed.
The door disarm switches are assembled into both LH and RH lock sets. The door disarm switch must be triggered before the mechanical lock unlocks. This is to prevent the anti-theft alarm from activating when it should have been disarmed.
The RAP module controls the anti-theft system and is the brains of the keyless entry system. The RAP module communicates with the GEM to request that the interior lights be turned ON/OFF with use of the keyless entry remote transmitter, and the GEM communicates to the RAP to inform when the door is opened. Refer to Section 418-00 for inter-module communication.
The RAP module has three wire connectors attached to it:

• The antenna for the keyless entry remote transmitter.
• 26 circuit connector (C256).
• 22 circuit connector (C257).

In addition to the perimeter alarm that uses the door open warning lamp switch, the RAP module also uses the ignition lock anti-theft switch and the autolock/relock feature to prevent theft of the vehicle. For a full description of the autolock/relock system, refer to Section 501-14B .
The THEFT LED is found on the instrument panel between the tachometer scale and the needle pivot point. The LED is illuminated during prearming and flashes when armed or triggered.
Prearming and Arming the System
The system can be armed if:

• The ignition is OFF.
• The PANIC alarm is OFF.
• All doors are closed.

There are two ways to prearm the system:

• Press the LOCK button on the transmitter.
• Open a door, press the power door lock button and close the door.

After 30 seconds the system will be armed and the theft indicator in the cluster will flash every two seconds.
Disarming an Untriggered System
An armed system will be disarmed with one of these valid actions:

1. Pressing the UNLOCK button on the transmitter.

1. Placing a key in the door and turning to UNLOCK.

1. Turning the key to RUN or ACC.

The anti-theft alarm can be triggered by the following conditions:

• The ignition cylinder is damaged with or without the RAP being armed.
• A door is opened without disarming the armed RAP module.

The remote transmitter can activate a panic alarm which is similar to an anti-theft alarm, but does not deactivate the starter or cause the theft indicator to flash.
Disarming a Triggered System
If the system has been triggered, (the horn honks, the lights flash, and an external starter interrupt relay is engaged), the system can be disarmed by:

1. Pressing the UNLOCK or PANIC button on the transmitter.

1. Putting a key in the door and unlocking the door.

1. Turning the ignition to RUN/ACC (Turning the key to RUN/ACC will not disarm an alarm that has been triggered by the ignition lock anti-theft switch.).

on the ignition key you have to change the ignition baril put new one in try to start it wont leave the key on theft light will flash for 20 minute turn key off and start it thanks pierre