I can't get hooked to computer on truck withobd2 code reader. they won't link up. what is possible problem? I checked the fuses, all are good.

Check all fuses includeing main fuse if all good. While cranking check for spark if spark present check for fuel pressure , if no spark test coil if coil is good I would suspect a bad computer if no fuel pressure you have a bad fuel pump

Check the cigarette lighter fuse. This is what powers the DLC. If the fuse is good, check and see if the lighter works. If not, you have a bad wire. Code readers have to have power from the car. Most scanners have there own power and will read the computer, unless the data wire is bad or the computer is bad.

It means the code reader cannot link up to and communicate with your vehicles computer/system controls. It could be the scanner or the vehicle causing the problem.

usually this is a cam position sensor I have found this problem many times by replaceing the camshaft position sensor I believe this will solve your problem if this is helpful please leave good feedback

you may need to hook up a code reader to erase it.

Do you have power to pin #16 of the data link connector, if not that is the problem find and replace the fuse.

Check fuses first, but could be needs new CPU

A professional scan tool,you can not afford or
or professional software,for a computer

You will only be able to afford a code reader & they
only read generic codes,not ALL info, as you suggested.

If you have no factory service manuals,you won't know
how your vehicles systems work

Then without the powertrain/emissions diagnostic manuals,
and possibly wiring diagrams,you won't have the reference
material necessary, to learn where to start any testing,once
you get codes

Try checking the "Main Relay" and its fuse.
Hope this helps.

On Board Diagnostics. There is a data link connector (DLC) inside the fuse box. you hook up an OBD code reader to this DLC and it will communicate with the engine computer and retrieve stored trouble codes in the computer´s memory.