[mmwmmw]

Hi.

I do not have the 12V on the Wake Up line from Junction Box to IBS.

ISTA shows a short circuit to the B+ on the Wake Up line.

I check the wire and everything is fine, there is no short circuit and there is continuity. If a plug is plugged into the Junction Box, the resistance between WakeUp and B + is 380 Ohms. And do not know if that value is correct. I have no other F10 to check it.

I suspect the Junction Box is damaged because honestly I see no other reason, since the cable between Junction Box and IBS is functional, and I have 0V on the WakeUp line on the IBS plug.

Any ideas?

I will add that when the battery is not fully charged, the car reports too much power consumption while the car is not in use.

[pawelkos]

Replace IBS sensor.

[mmwmmw]

Have You read my problem description? I wrote clearly that there is no 12V on the WakeUp line. What does IBS sensor have to do with it? I made a very detailed description of the problem in order not to waste other people's time and my own.

[Node]

Well I will WASTE YOUR TIME even more, because I'm evil And because it's IBS which usually dies and short circuits that line to ground. Have you tried disconnecting plug on IBS and THEN checking voltage on that line???

[mmwmmw]

Yes, You are evil. ) Of course, I checked the voltage on the unplugged plug. After all, I wrote clearly that I checked this wire between JBBF and IBS if it has a short circuit or break and that 12V is not coming from JBBF on this line.

I also wrote that ISTA gives a short to B + and not to ground.

[Node]

Frankly your writing does not make any sense. You say there is a resistance of 380 ohms (quite small) between B+ and that line in JBBF. But in such a case THERE SHOULD BE 12V on that line. You really need quite good short to ground to overcome that.

So have you measured that resistance with battery(-ies, if there are multiple) disconnected or not? If not - that measurement is bollocks.

Have you measured resistance to ground? What is it then? If not you should measure it. Because that resistance to B+ could well be roundtrip through the short to ground.

[pawelkos]

[b]mmwmmw[/b]


I did, look for the diagram.

[mmwmmw]

I checked the E90 LCI and with the IBS plug disconnected, 12V appears on the wakeup line. In F11 it does not appear. For some unknown reason, when the ignition is turned on, the JBBF doesn't give 12V on that wire. In my opinion, this has nothing to do with IBS, because since it's completely unplugged it doesn't affect what JBBF does. Right?

[Node]

I checked the E90 LCI and with the IBS plug disconnected, 12V appears on the wakeup line. In F11 it does not appear. For some unknown reason, when the ignition is turned on, the JBBF doesn't give 12V on that wire. In my opinion, this has nothing to do with IBS, because since it's completely unplugged it doesn't affect what JBBF does. Right?

That's why first thing to be tested in such a situation is to disconnect IBS. However in your case it's clearly not the problem.

So 2 possibilities remain: 
1. You have a short to ground on that line somewhere. Don't see any argument provided against this yet.
2. JBBF (or some other unit) is faulty. However given small resistance from that line to B+ this DOES NOT MAKE ANY SENSE as you say voltage on that line is 0V. Hence my questions about how you measured it and whether you measured resistance to ground.

[mmwmmw]

With the battery disconnected, there is 2kΩ between WakeUp and B +. There is 1 kΩ to the ground, if I remember correctly. Basically, I just measured it to find out why ISTA is giving me a short to B +. I think that this information is registered by the JBBF.

I wrote at the beginning that I checked this line when was disconected and there are no short circuits and there is continuity.