Want to program 4 new chip keys in1998 ford explorer

The chip in the key is part of the anti-theft system and immobilizer. Did the vehicle start after the fuel pump was changed? It is normal to disconnect the battery when removing fuel pump, and after a battery disconnect, the anti-theft system need to be reset.

1. Insert the key into the driver's side door lock.
2. Turn the key once, but not all the way to unlock the door. Leave the key in this position for 40-60 seconds. ...
3. Do this again, but turn the key in the opposite direction.
4. Remove the key from the door, get into your Ford, and start the engine. The system should be reset.

How to Reset the Anti-Theft System on Your Ford

https://www.google.com/search?q=ford+explorer+pats+reset

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The old key may have an induction chip in to deactivate the anti theft system. Does it have a red insert (chip) in the key handle? Get the old key and place it as close to the ignition barrel as possible. Seen this done on a number of occasions to save paying for a key reprogram.

are you using a key copy, w/o a chip in it? if so, it will immobilize. if it's a new key "with" a chip, it needs to be programmed.

sounds like you got bad information. if you call the dealership they will make a new key and program it to your ignition.

just ask for the key first you can get a used remote form my be ebay and used your owner manual info.to program it if the key had a chip in it,will cost you $100 or so the remote mybe $20

There no way runs through your computer, your truck is in theft mode, most lock smiths have the computer to program a chip to your pag system, you have a key already won't be that much to do.

Pats system is not seeing your key.Look at the end of the key and make sure chip did not fall out. Do you have another key? The only problem with this is to program a key yourself you must have 2 working or programed keys. If you don't then you have to have a scan tool that will perform security access to program another key. The dealer can of course do this and now some locksmiths have this technology also.

No you will need the key with the chip in it or the truck will not run. The key has a transmitter in it and when you put it in the ignition it sends a freqwency out and that is how the truck starts or dosent get stolen if ya dont got the key.

That's a very good posibility. If the anti-theft light flashes rapidly when you try to start the car with the suspect key, you will need to have a dealer program the keys. Good Luck and please leave rating.

Yes I agree it's the 'smart key'. Normally when you buy an explorer new, you will get 3 keys. 1 of the keys is a valet key.
If you were to copy another key that has a smart chip (transponder) in it, the new key won't work until you 'program' the third (new) key. To program it you need the original 2 keys that work.
The only other thing could be that there was a remote start in the vehicle and there could be something wrong with the module that bypasses the transponder. If there is a remote start in the vehicle you might be lucky to some extent if it still works.
If you move the shifter hard and it worked before, like you said, there could also be damage to the wires that goto the key cylinder, the reciever for the transponder in the key. Try having someone hold the key in start and use the tilt wheel, that too will tell you theres damaged wires if it starts.
Unfortunately you probably will have to bring the vehicle to a ford dealer to get additional keys programmed or the damaged part replaced.
It shouldn't cost too, too much. Just be glad you don't have a Saab, replacement key's are $145 Ea!
If your inclined, you can dissassemble the plastic shroud around the steering column and look for damaged wires coming from the black ring around the key down the the connector under the dash.