2007 S60 Codes, disable

[rcooksey]

2007 S60 114K. Last week check engine light came on. Code reader said something about evap system. I cleared it an drove a few days until it reset monitors. Checked with reader yesterday and car did not want to start with reader plugged in plus message on dash said transmission service required. Went to emission station this morning and Tester said I had a communication failure code and it would not pass. When she attempted to start car with her reader attached it started and cut off until she removed it. Cleared codes again, returned home (10 miles)and got drive cycle. Plugged reader in and drove off, would not change into low gear, at bottom of small hill I got a brake failure light, returned home, not in low, then got speed sensor code then car cut off and said disabled. Unplugged reader, waited, life passed before my eyes, then restarted. Ran fine, shifted, no additional lights, messages (anti skid has been on and off for months). Cleared codes again, drove through drive cycle, back to inspection station (different one) and it passed. Drove around stopped several times. Runs great, no codes, no messages on dash, except the anti-skid. Is this related to reader being plugged in maybe not all the way?

[draser]

I'd get a loaner code scanner and see if you can duplicate symptoms. Does car start easy, and are batt. posts/clamps clean and tight?