2004 S60 Troubleshoot heat soak ECM, BCM, CEM, & TCM Topic is solved

[GDiode]

I had the same issue with my wife's "03 XC70. After paying $600 to Xemodex to have the DIM rebuilt 3 months ago and buying the car for $1600 2 months before that I wasn't able to fork out another $500 to have the CEM rebuilt also. I was getting the same symptoms: ie 'Brake failure' message; check engine light on; AC stops running; cruise control stops; a couple of times if I didn't stop and turn the car off and back on the transmission clunked. I got the DeOxit contact cleaner on Amazon and pulled each of the black fuse boxes/relays out of the CEM spraying the metal tab connections with the DeOxit, letting them dry a couple of minutes then reinserting them into the CEM. My original plan was to spray the connection that goes into the CEM. But I couldn't figure out how to remove the wire harness (and I was running out of light in the day and would have to be up at 1:30AM to start my day (got to love the bread business). I don't know if the metal tabs were not making good contact and so breaking the continuity in the system?
It has been 3 weeks and I have not had the problem again. It had been acting up almost daily. So your my trying the DeOxit early in the process seemed to do the trick. So far. Thank you for the DeOxit suggestion.
I do plan on adding the small computer fan that mrbrian200 posted about to keep it cooled down.

Shannon