[ArcziArcz]

Hi, I have F02 in garage 6.0i N74 engine and there is fault CD9001 Lin message auxilary coolant pump for charge air cooler. There was no + on it due to other problems but now I repaired it the + is now ok and the pump is working normal. I sart it from Ista and it is working and from normal venting as I plug accelerator pedal for 10 sec it get started normally. I check the wiring of LIN form pump to DME and it is ok. I plug new pump try to delete codes but there is still same fault. So it is not pump problem not wire so DME would not read LIN ? Ihave no other fault relating LIN so I am confused. Anybody have any idea ?

[Mwahab]

If you are sure 100% that wire is connected and u replaced another pump to test, then its DME issue now.

[masa52]

check the other unit connected to that LIN line
Definitely there is more than only one connected to LIN bus

[ArcziArcz]

Yes there are other lin users but there is no error in car according to any of them. Despite that from pump to dme its only pump on this pin other users must be on other wiring

[Node]

IMHO you need to check whether those LIN pins are just connected one to another inside DME. In such a case malfunctioning another thing on the same bus (like IBS) could randomly short bus out or otherwise disrupt the communications.

Or you could just try to disconnect IBS and see it that helps with you problem.

[ArcziArcz]

Ok so there are 2 dme in this engine but only in dme 1 are Lin bus connections pump is on pin 56 on connector x60002 and Ibs is on pin 37 in connector A46.  So there is completly other wiring. When I unplugged IBS itsa reports me LIN/BUS error and the error from pump completly disappear. After I plug IBS delete errors the LIN/BUS error going off and pump one appear. Now I change cables in connectors just swipe pin 56 with 37 to see what happen and I have now on ISta only lin bus pump error ;D And no ibs error I am so confused right now.

[Node]

Given IBSs are known to do FUNNY things, I would assume that it somehow interferes with pump coms. No way to tell for sure unless you look what's going on using oscilloscope.

[masa52]

I have had a similar situation in S63 engine where IBS was erroring but at last one of the auxiliary pumps was dodgy

[inspi1981]

Did You change correct pump?

[JBScuba]

Very unlikely that it is the DME since it only faults 1 item on the LIN. You can rule out the DME by swapping them bank to bank if you really think that is the issue. An opened up or burnt pin on the pump connector could do it as well.