If you have a stroke, certain cells in your brain can die, and ultimately leave you with some serious health concerns. Sometimes the after effects of a stroke manifest them selves in the form of partial paralysis, numbness of certain body parts, even the loss of the ability to speak. While the human brain is many times more advanced that the computer that controls your 2004 F150, your F150 may show some of the same type of symptoms when its brain “strokes” out. The engine may not start, and if it does, it will run poorly. The PCM won't deliver signals to various sensors and relays as it should – ultimately leaving your truck in a working condition much worse than what it once was, if it can even carry on at all. Unlike us, your truck is a machine, so its brain can simply be replaced with one that does work, after the proper programming. Come to think of it, wouldn’t that be a nice advancement in human medicine?
Have your new or used PCM programmed to your truck's VIN number. Some auto parts stores can do this for you, or you can have it done at a Ford dealership.
Raise the hood. Loosen the nut on the negative battery cable, using a socket and ratchet. Pull the negative battery cable off of the battery terminal. Look at the firewall, on the passenger side of the engine bay, and locate the powertrain control module.
Pry up on the locking handles for all three harness connectors on the PCM, using a flat-head screwdriver. Disconnect all three connectors from the PCM. Remove the four bolts that secure the PCM to its bracket, using a 13 mm socket. Remove the PCM from the engine bay.
Hold a new PCM up to the PCM bracket, then snug the mounting bolts. Guide each wiring harness into their respective connectors on the PCM. Push down on the locking tabs to secure the connectors in place. Install the negative battery cable, then snug the securing nut.
Insert one –the primary -- ignition key into the ignition, then turn the ignition to the “On” position. After a minimum of three seconds, turn the ignition off and remove the key. Insert the second key into the ignition and turn it to the “On” position. After a minimum of three seconds, turn the ignition off and remove the key. Insert the primary key into the ignition again and turn the ignition to the “On” position. After a minimum of three seconds, turn the ignition off and remove the key – Both keys been reprogrammed to the new PCM.
