Could not smog my 2001 S40 with check engine light on. replaced oxygen sensor and took to Volvo repair person with proper computer software who told me TCM was kaput and needed new one to be able to get further data of codes from transmission to learn the problem.
Since cost of new one was quoted at about $800 with $200 installation, I purchased used one on line. Mechanic says he is not sure TCM from one car will work on a different car--. Wants me to first check -- but why can't a used one be programmed to my vehicle if a new one could? Anybody know this? Will I have to return the used TCM and get a new one ? Thanks!