OMG Chilidawg,
Toyota is not in the business of "helping" people
Try buying a parts manual from them. It's encrypted with gibberish part numbers that only Toyota can decipher.
Edward t is right on. Rarely do we need a scan tool or laptop to diagnose a truck. If i followed Raymond diagnostics from factory manuals each time, i would need 4 hrs minimum diagnostic time. I dont know what the guy who wrote those manuals got, but it should have been life!
Raymond is owned by toyoda so the apple doesnt fall........
I've just recently started servicing 6,7 and 8 series trucks. No manuals. Found tons of help in these forums that saved me big time. Lots of common sense issues fix these trucks. Many codes turn out to be nothing to do with what manual lists as probable fault. Tried and true remedies from the blood sweat and tears of "hands on mechanics" always beats pencil pushing "iron ring syndrome" engineers!

I would expect that if it was a 4.3 GM with an impco spectrum system, and you find the plug, the impco software may help some.
you do recognize that about 95% of what goes wrong does not need a computer to diagnose?