Thread: OBD code 0740 on 1997 740iL

Could be the alternator on its way out as the code is defiantly a transmission code , if the voltage is not stable it will affect the transmission solenoids especially the torque converter pressure regulator and throw up codes, Ive heard of boxes going in to TRANSFAILPROG just due to the battery being to old and not holding the voltage, as your lights are flickering its either the Alt or Batt or...

I now the battery looks brand new, ( not necessarily my prefered brand ), I'll check the alternator output this weekend to see if in fact the alternator is the culprit, thx

The trouble with alternator tests is they dont test them under load or at say 4000rpm at tick over it maybe fine, so to test it you need to be in 'D' with the foot and hand brake applied up to 4000rpm and test it at all rpm ranges, I had one that only started to fail at 2500rpm at idle it was perfect.