Diagnostic Code Info

I'm trying to figure out three codes that pop up on my buddy's 1990 Oldsmobile Regency (3.8L). I saw the thread just below this one that appears to be a related topic. However, the three codes I need to figure out are not listed on the web site that you can link to. I can understand one of the three codes not being listed, but none of the three are there.

The codes I get are a code 26, code 64, and code 65.

If anyone can tell me what the codes are, I would greatly appreciate it.