[Node]

You need to find out which unit EXACTLY reports that fault. Wakeup line DOES NOT END at JBBF. It goes to many other units after it depending on car year, engine type, etc.

[mmwmmw]

You need to find out which unit EXACTLY reports that fault. Wakeup line DOES NOT END at JBBF. It goes to many other units after it depending on car year, engine type, etc.

The short circuit to B + error does not always appear. I attached a screenshot of ISTA. Please take a look.


Sometimes, after erasing the errors, only the LIN error, that is communication with DDE, appears and it is a permanent error. Sometimes there is also an error from JBBF about shorting to B +.

As I wrote in the first post, LIN has the correct value of 9V, terminal 30 gives 12V. Only JBBF's WakeUp doesn't show up at all.

[Node]

Faults would suggest that IBS is dead (I assume IBS was connected when this was read).

Reasoning:
1. JBBF is NOT even connected to IBS LIN. So that fault is most probably registered by DME/DDE which is the primary unit IBS speaks to.
2. Don't know which unit registers wakeup line fault, but if it's JBBF then two different units register faults on two different wires. The only common place for both is IBS.

As I already said you should figure out WHICH unit registers that fault. Tried to lookup those faults with ISTA, but couldn't match any F10 car to those.

[mmwmmw]

I'm sorry, but you don't read carefully what I am writing. I wrote that the LIN error is from DDE. Short circuit error from JBBF.

I don't know how JBBF handles IBS, but it may be that when JBBF gets signal from DDE about communication problem over LIN, it doesn't give 12V to wakeup and in fact IBS is broken. That's why I put the topic here, because I was hoping that someone had already had such a case and had experience in this matter.

[Node]

It's summer, I'm on vacation, so it's not my job to read carefully

AFAIR you said you measured 0V on that line which is normal if the car is with ignition off (asleep).

Wake-up line is NOT controlled by IBS. IBS NORMALLY is just receiving the signal. Don't remember which unit controls it on F10. It could be JBBF. Which then would mean that SOMETIMES SOMETHING holds that line high while JBBF is trying to pull it low. Hence short circuit to B+ fault.

Given the DDE fault I would still bet your IBS is kaput. And SOMETIMES it just so happens it shorts wake up line to B+ so JBBF (or whatever other unit) is trying to pull it low just is NOT able to do that.

One of the typical behaviours of bad IBS is that it goes crazy and pulls low or high different signals randomly. And you are lucky it does not pull it low because then the car is unusable.

[mmwmmw]

I obviously checked the wakeup line going to the IBS with the ignition on. It is quite obvious. I also didn't write that IBS controls this line. I wrote that a error in the DDE can cause a JBBF reaction that stops the wakeup turning on, or the JBBF sees a short circuit in the IBS and inhibits the signal.

All in all .. IBS can be bought for around £ 15 so I will just buy it and check it out.

Vielen Dank.. and have a nice holiday.

[Node]

I just explained how it works to prove my reasoning and diagnosis. And DDE fault is definitely not related to JBBF fault in a way that it's DDE fault causing JBBF fault. That is just not how it works.

In the case JBBF fault remains after IBS replacement could mean you have two faulty units in your car, but IMHO that is highly unlikely.

[willisodhiambo]

Deal with the LIN bus issue first. Check wires, if ok get a test IBS.

[papachivas]

Hello friend, as you said that there is no 12V in the wake up for you to solve this part and rule out the possibility of failure in the IBS, just remove the wake up terminal and add a direct supply 30+ if the Lin fault remains you have an IBS with defect.  In relation to the lack of 12v power supply in the wake UP line, provide information on the wire regarding a breakage of the same, the origin of the wake UP line and the CAS for several units, all according to your vehicle equipment model and manufacture the ideal is to check if the origin is the CAS or JBE as we do not have the VIN number of your vehicle

[mmwmmw]

Good idea. It is embarrassing that I did not think about this simple solution to diagnose.

Fortunately, IBS was the problem. I bought the latest version with the current number from ETK for 15 pounds and everything is ok. Probably JBBF, seeing the short circuit, disconnected Wakeup, so it was impossible to measure it, after disconecting the plug.

Thanks to everyone for Your help.