On Ford/Lincoln/Mercury PCMs we offer VIN & Firmware Update programming.
Ford uses PATS (Passive Anti-Theft System) on many vehicles. Some owners do what's called an IMMO-box delete to bypass it however if it's installed it will check for any foreign control units and prevent the vehicle from starting if there is a security mismatch.
We don't do any PATS bypass services or sell harnesses for this. There's plenty of such products that can be found on Amazon.
However, if for example a customer doesn't have the original PCM and purchased a replacement where they plan on getting it programmed by us, we can change the VIN and latest firmware update on it but depending on the year and model, they might need to perform an extra step.
Our programming-only service will change the VIN and calibrate it to the vehicle. However, because many Ford vehicles use PATS (passive anti-theft system) that synchronizes all the modules to each other, this can only be done in-vehicle where the PCM is actively paired to the vehicle and keys.
Basically this is an added step for the customer that they must be aware of. Not every Ford vehicle is equipped with this however if it is, the customer will need to have the locksmith program the keys to the PCM in-vehicle. This in-vehicle service typically costs $100-150 depending on the where the customer lives (pricing is subject to change).