A short while ago I had a aircon pump fitted and on the morning I was due to drive to the garage, I thought the battery was flat (pretty unusual because I drive the car regularly with no problems) as it was intermittently trying to turn over, I noticed the motor control unit failure light came up a couple of times.
However I ignored it thinking it was because the battery was down. I discovered the fault was that the positive connector wasn't gripping the battery post. I took the opportunity to charge the battery and with a metal 'sleeve' wrapped around the post achieved a good tight fit.
Still got the warning showing, so I did the manual ECU reset suggested on this site, however although improving the performance considerably I've still got the warning - any suggestions?