Vehicle is in anti-theft mode and will not start.

Question edited for clarity and toss in some CAPS.
Question moved to model category.

You can't if by 'take off', you mean bypass or disable it. The anti theft system is there to stop what you are trying to do, drive the car without the correct credentials, key chip to the ECM. Just reset it.

How do i perform the 2009 Ford Flex anti theft reset?

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Jul 16, 2020 - Resetting the anti-theft system in Your 2009 Ford Flex is easy to do, and will take around 8 to 10 minutes of Your time. People also ask
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I have a 2009 Ford flex that's stuck in antitheft mode. What

JustAnswer https://www.justanswer.com > Ford Repair
Oct 30, 2022 - 1-Disconnect both battery cables, positive & negative. 5- Reconnect battery positive first, then negative post.

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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.

You do not have a problem with the anti-theft system , if the vehicle starts when you get a jump, you have a battery or charging system problem. It is not stuck in anti theft mode ??? Your best bet lady , take it to a qualified repair shop .

Why ? Anti-theft system problem ? The ignition switch on this vehicle is a input to a control module (BCM) body contol module !
This vehicles BCM functions as the Power Mode Master (PMM). Refer to Power Mode Description and Operation for a complete description of power mode functions.
You could probably get the engine to crank but if the system doesn't see a coded message from the transponder in the PASSKEY 3 key the anti-theft system software won't let the vehicle start and run . Plus the steering wheel may not unlock and also it may not come out of gear ! Can You Hotwire car Like in the Movies Hollywood Secrets Revealed

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.

Make sure that the battery is in a fully charged condition and reconnect, Positive post first and then the negative (This helps to avoid accidental short circuiting) Close all doors, bonnet/hood boot windows etc. Lock the vehicle with the key. Leave vehicle for at least 10 minutes without disturbing it. Unlock vehicle and start the engine. I have had to use this method on various makes of vehicle. It allows the system to reset. PLEASE NOTE the battery must be fully charged.

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.

if the vehicle starts then stops and the anti-theft light is flahing you may need to re-set the pass-key system to do this you will need to atempt to start the vehicle and when it stalls leave the key in that position and watch the anti-theft light. it should flash on and off for about 5 to 10 minutes. when it stops flahing turn the ignition to off then try to restart your vehicle