The dongle corrects the problem that the T21 firmware change in the ECU triggers with the 2004 instrument cluster (IC).
So
(a) FIRST you get the T21 recall performed
(b) which THEN causes the Sprinter to flatten its battery overnight, since you don't notice that the IC display doesn't go dark after 45 seconds.
(c) the quick work-around is to turn the key on, then off again, pull it out, and the display WILL go dark 45 seconds later.
(d) the OLD fix was to replace the IC with a newer model. MB has run out of that part.
(e) the NEW fix is to add that dongle.... it apparently notices that the van is off, and sends the appropriate command over the CANbus to truly shut the Sprinter down.
You could consider the dongle as a band-aid to correct the wound caused by the ECM firmware update.
The firmware update makes the ECM notice problems with the MAF. Prior to the recall/update, it was ignoring them.
--dick
I see (said the blind man).
So van will still get the error code related to communication with IC?
Still have to go to the smog referee for certification here in Cali.
Sounds like SOS is still my best bet.
Thanks!
Jef