I am new to this forum and need help. I replaced the computer and the car will not start, it is a 1998 mustang gt. i believe its the key that needs programing but how? Please dont tell me dealership

 

Here is a link to reprogram ignition key(s).

How do you program security keys on a 1998 Mustang? | The Mustang FAQ

 

The mustang was built 08/97 so that puts it as a early build for a 1998, so then method "B" should work

 

Should work from '96 to '98.

 

I just went thrue the instructions and nothing, it was not able to goe the 15 minutes. it flashed for only 2 to 3 minutes each time and i waited within the 5 minutes. I noticed that the blue connector that says the top side is reversed from the oem computer, and putting the computer in is upside down. It may be possible to reverse the board and still work, so i do not know. I hope that some light can be shed on this issue

 

Do you mean the 104 pin connector at the PCM, Powertrain Control Module (computer) is plugged in upsidedown?

 

Yes the connecter on the computer has printing that says this side up. The stock computer is oppisite the replacement on, in other words the case mounts upside down oppisite from the other. I took the cover off both of them and it looks the same. It appears the case is the problem, the board is on the oppisite side of the case

 

Double check, and make sure that is the right PCM for your Mustang. That the female and male connectors match perfectly.

As long as you can securely mount the PCM, and the wiring harness, and connector reach the case, configuration shouldn't really matter, and method "C" key programming may be your only option. Method "B" may only work if you already have a master key, a key that works, and you want to make duplicate programmed keys.

However, a lot of red flags go up about errors in part reference, and assembly mistakes. The alphanumerics stuck on the case may be a mistake.

I wondering too, did you need a re-program flash on the '98 PCM?

 

I was told it was flashed before being sent and the sticker says so. The original keys do nothing when turned on, but i have a spare key that was not programed, It was under the carpet when i bought it new, i found it changing the seats. When i use that key the theft light does flash ,but only for 3 minutes each 3 times and will not start the car

 

Method "C" then. Dang.