as it states the nano will not connect to the ecm but it will connect to the becm. this is a friend's car he has asked to fix air bag issue but i cannot connect to read the fault . where is the best place to start .
I think the engine needs to be running to connect to the ECM, and not running to connect to just about everything else? (I could be completely out to lunch on this).
hi Harv just gave it a run , didn't work , every thing else worked but it will not communicate with the air bag system . just comes up with, unable to communicate with ecm.
Well, not much info to start with ... what "ecm" are you talking about? Engine? or airbag?
If you cannot connect after a few attempts (I have such issues with the hevac, he connects randomly), consider the possibility that the airbag ECU has no power, and therefore does not "talk" at all. Is one simple option (check fuse), but to get to the ECU you need to get some stuff out ....
To connect to the BeCM the ignition needs to be Off, for all the others, it needs to be On (engine running or not). Are you trying the correct airbag ECU? Assuming you mean SRS, there are different ones fitted to different years and markets, MPS for very early cars (and US models) with the two crash sensors behind the headlights, SPS1 for the GEMS and SPS2 for Thor. You need to be using the correct one.
Otherwise, OBD signals go via the large connector in the RH kick panel and different circuits use different pins in the OBD connector, SRS uses pin 14 (and 13 on MPS) which isn't used by any other circuit.
Additionally, accessing the HEVAC diagnostics is always temperamental. Nanocom docs also mention that it can be more difficult if BECM is unlocked. I have found this one works best with engine running.
Just because Nano says it can't communicate with the ECU it doesn't mean it's true...i was using mine just yesterday to interrogate the EAS and it gave me the same "can't communicate" message on the faults screen but all the ride heights popped up on the Inputs screen with no problem, including the live data
thanks for the comment Harv , straight to the problem, blown fuse under the bonnet . i am refreshing an old rover for my daughter's wedding soon, have been cleaning it up for registration . lets hope the fuse didn't blow for a reason , thanks.
Nice! Old Rovers at weddings are a great idea. My oldest daughter had my patina 2A in her wedding and photos.