Ok i lost the only key with my remote so i bought a new ignition with keys .my boyfriend install it .but it wont start cause the anti theft system wont let it ,on 1998 ford crown victoria ..

That is because the switch must be paired with the ECU. Anti theft has activated. Call your local garage for assistance.

Hello. It seems the new ignition switch/lock cylinder won't 'communicate' with your vehicle's anti-theft system; causing it not to start/run normally. That ignition switch/lock cylinder must be 'programmed' by a 'certified' locksmith shop. They have equipment to 'pair' the switch and your car's anti-theft system together. Good luck and keep me informed; if you want to.

The PATS - passive anti-theft system is a program (software ) programmed into the instrument cluster , PCM - engine computer , GEM module etc... Plus behind the plastic shroud on steering column where the lock cylinder is located the passive anti-theft transceiver module ! You better know what your getting into when you start to mess with anti-theft systems , you can render your vehicle useless if your not careful ! Need factory scanner to program keys , to read trouble codes , check data etc... If you change transceiver module it will need to be programmed ! FORD DEALER ONLY ! You can program more keys but need to have original two keys that came with the vehicle or you can't do it >
Passive Anti-Theft System (PATS) -Principles of Operation 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 out of over 18 billion, billion combinations.
The passive anti-theft system (PATS), also known as SecuriLock ®, uses radio frequency identification technology to deter a drive-away theft. This system is known as SecuriLock® in North America, Safeguard® in the U.K., and PATS in Continental Europe. Passive means that it does not require any activity from the user.
The SecuriLock® System (PATS) is not compatible with non-Ford aftermarket remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. If equipped, the remote start system must be removed before investigation of PATS-related, no-start issues.
Each encoded ignition key must be programmed into the vehicle powertrain control module (PCM) before it can be used to start the engine. There are special diagnostic repair procedures described in this section that must be carried out if a new encoded ignition key is necessary.
The correct ignition key is a different design than prior model years. Please consult the Rotunda Key Ordering Guide for the correct part number.
So , before messing with something you know nothing about , do yourself a favor , take it to the nearest FORD dealer !
So

The battery reset protocol usually means the 8 turns routine using the original keys with key fob transponders
Turning the key and moving the shift from park to drive and back again has helped some people
More information here

https://www.cargurus.com/Cars/Discussion-c112_ds558688

Possible anti theft but I think that you have a blown fuse go to ford owners manual.com and register for free then download the manual then go to roadside emergencies and your fuse box diagrams and values for ignition and fuel pump as well as others //// when you put the key in does the pats system light start to rapidly flash or does it go out while cranking if rapidly the anti theft is activated or somehow your key was erased check PCM fuse ignition fuel pump coils injectors

TURN ON IGNITION SWITCH TO ON POSITION.ENGINE OFF.REPEATEDLY PRESS VECHICLE INFORMATION BUTTON UNTIL PRESS TO RELEARN REMOTE KEY IS DISPLAYED.PRESS SET RESET BUTTON UNTIL REMOTE KEY LEARNING ACTIVE IS DISPLAYED. IF THAT PROCEDURE DONT WORK.INSERT MASTER KEY INTO IGNITION SWITCH.NOW SWITCH IGNITION ON SWITCH IGNITION OFF.REMOVE MASTER KEY.WITHIN 10 SECONDS INSERT NEW KEY.SWITCH IGNITION ON.ENSURE SYSTEM WARNING LAMP SWITCHES OFF.NEW KEY NOW PROGRAMMED.IF YOU STILL HAVING PROBLEM RESETING THEFT SECURITY SYSTEM THE DEALERSHIP HAS TO FIX.REPROGRAM IT.

does it have a remote start in it some times they can cause problems or you need a new ing switch and if the anti theft light comes on and the car wont start but turns over put the key in the ing switch and leave in on pos for 15 to 20 min to reset anti theft system.

try using spare key might be the anti theft system does not recognize this key also if you have a remote car starter use it if it starts this way you have to get a new key but if not you might need a new ignition switch and then dealer has to reprogram the anti theft system. try lock smith key places some can use your vin number to re-cut you a new key much cheaper then the dealer.

alarm rearms itself.

this is for 2001 and is similar.

Anti-Theft —PATS The passive anti-theft system (PATS) contains the following components:

• theft indicator
• encoded ignition key
• transceiver module
• instrument cluster
• powertrain control module (PCM)
• standard corporate protocol (SCP) communication network

The PATS uses radio frequency identification technology to deter a driveaway theft. Passive means that it does not require any activity from the user. This system is known as SecuriLock® in North America, Safeguard® in the U.K. and PATS in continental Europe. This information can be found in owners literature.
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, with over 72 million billion combinations.
Each encoded ignition key must be programmed into the vehicle's instrument cluster (the instrument cluster is also known as a hybrid electronic cluster [HEC]), before it can be used to start the engine. There are special diagnostic procedures outlined in the workshop manual that must be carried out if new encoded ignition keys are to be installed.
The encoded key is larger than a traditional ignition key. The key does not require batteries and should last the life of the vehicle.
The transceiver module communicates with the encoded ignition key. This module is located behind the steering column shroud 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 the data to the instrument cluster.
The control functions are contained in the instrument cluster. This module carries out all of the PATS functions such as receiving the identification code from the encoded ignition key and controlling engine enable. The instrument cluster initiates the key interrogation sequence when the vehicle ignition switch is turned to RUN or START.
The PATS uses the PCM to enable or disable the engine. The instrument cluster communicates with the PCM over the SCP network in order to enable engine operation. The instrument cluster and the PCM use sophisticated messages in order to prevent a theft. The instrument cluster and the PCM share security data (when first installed together) that makes them a matched pair. After this security data sharing, these modules will not function in other vehicles. The shared PCM ID is remembered even if the battery is disconnected. The instrument cluster also stores the vehicle's key identification code even if the battery is disconnected. There are special diagnostic procedures outlined in this workshop manual that may be carried out if either a new instrument cluster or PCM needs to be installed.
All elements of PATS must be functional before the engine is allowed to start. If any of the components are not working correctly, the vehicle will not start.
PATS uses a visual theft indicator. This indicator will prove out for three seconds when the ignition switch is turned to RUN or START under normal operation. If there is a PATS problem, this indicator will either flash rapidly or glow steadily (for more than three seconds) when the ignition switch is turned to RUN or START. PATS also "blips" the theft indicator every two seconds at ignition OFF to act as a visual theft deterrent.
The PATS is not compatible with aftermarket remote start systems, which allow the vehicle to be started from outside the vehicle. These systems may reduce the vehicle security level, and also may cause no-start issues. Remote start systems must be removed before investigation of PATS-related no-start issues.

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Visual Inspection Chart Mechanical Electrical

• Ignition lock cylinder
• Encoded ignition key (PATS key)
• Use of non-encoded ignition key (key without the molded plastic head, non-PAT key)
• Use of a non-programmed encoded ignition key

• Central junction box:
  • Fuse 2 (5A)
  • Fuse 6 (5A)
  • Fuse 30 (30A)
• PATS transceiver
• Connectors
• Ignition switch

The chip is in the key. Either the key has lost it's program or the transceiver is not recognising the key. Try another key if you have one.