X10116: where to locate in Z4M

[RossBMWZseries]

Yes sir it was disconnected while I worked on it. I haven’t had any sleep, I started the car this morning just fine. Came to autozone to buy a few things and now the car doesn’t start. Battery was replaced in May. So here I am stranded. Things can’t get any worse with this car

[NGAAutoTV]

That group of wires taped together is the KBus junction.

It sounds strange, but I chased this same thing last fall. I bought a 2007 BMW Z4 3.0i (03/07 build date) as a no start/flood car from Copart. I was trying to look for this same connector because I knew I had a KBus problem. But I found there was no bus bar or connector. I found that same bundle of wires taped as you found.

To be sure, I pulled the light switch, instrument cluster, and radio/nav. I check the KBus wire on those connectors and found it was shorted to ground. I continuity tested that bundle of wires taped together and found the wire bundle had continuity with the KBus wires for the components I removed. If you pull the tape off, you’ll find there are sets of wires grouped together with jumper wires in between each group. This effectively is the KBus junction. I can’t attach pictures, but can share essential the same thing as you found under the passenger side dash.

In my instance, I got the car running by cutting the bus apart (labeling and marking each as I cut), then checking for the single wire from the cluster. If I remember correctly, the cluster is the bus master. I then incrementally reattached wires back onto the bus until everything was reconnected. With the bus shorted to ground, my scan tool and ISTA+ could not communicate with the car. Once I “rebuilt” the bus, I was able to get ISTA+ to connect and then ran a measures plan. I ended up resyncing the EWS and DME to get the car started. Hope this helps you.

[NGAAutoTV]

Originally Posted by RossBMWZseries

Yes sir it was disconnected while I worked on it. I haven’t had any sleep, I started the car this morning just fine. Came to autozone to buy a few things and now the car doesn’t start. Battery was replaced in May. So here I am stranded. Things can’t get any worse with this car

Can you connect using ISTA+ or a BMW scanner and pull any codes?

Will the car start with the MAF unplugged?

I also have a Z4M Roadster and it’s done this once. I pulled the MAF connector and the car started right up.

[RossBMWZseries]

Thanks for the response NGAAuto. Another member did mention that his 2012 135i had the K bus junction set up exactly as yours and mine; just taped up with rubber caps at the end. Very interesting you mention this. I don’t have ISta+ but did pull a few codes with my scanner when it was able to communicate with the car. At this point the car is not starting, I don’t know if it’s the fuel pump or something I messed up further when messing with the wiring. Just tried starting it with the MAF unplugged but still no juice. Here’s a few codes i got the last time I scanned it;

* INSTR Instrument Cluster
* LSZ Light Switch Centre II
* ABS-DSC Dynamic Stability Control
* Engine-DDE Diesel Electronics DDE3.0
* Airbag-ACSM crash safety module

In detail;

87 KOMBI: K Bus
BE KOMBI: Data filing difference to central light module

1E LSZ2: Control unit fault in HVAC section
1F LSZ2: Coils, stepping motors, faulty
39 LSZ2: high beam/side light, left, faulty

2C92/present DME: exhaust-gas temperature sensor, electric
2F80/present engine switch-off time, plausibility
29F4/not present DME: catalytic converter conversion
29F5/not present DME: catalytic converter conversion 2
2A9C/not present DME: crankshaft sensor
2A8A/not present DME: inlet VANOS, adaptation stop
2A8C/not present DME: exhaust VANOS, adaptation stop
2A19/not present DME: Tank-venting valve, activation

0F Voltage supply, EWS3 Control module

93C3/not present ACSM: seat-occupancy detector, passenger
93FB/not present no message (vehicle speed) from DSC, ACSM receiver, DSC transmitter

5E1A/not present DSC: engine management, interface
5E20/not present DSC: hydraulic unit pressure sensor, internal

30 GM: K bus data transmission disturbed
D GM: anti-trap protection for power window unit, front, driver’s side
E GM: anti-trap protection for power window unit, front, passenger’s side
2C GM: relay for power window unit, front, driver’s side
88 GM: anti-theft alarm memory, engine-bonnet/hood contact
90 battery voltage: open circuit

[NGAAutoTV]

OK, so looking at that code list, it does seem like you have KBus issue. So the Kombi is your instrument cluster and should be the bus master. The central light switch is your light switch for your headlights. Your cluster and headlight switch share data and are on the Kbus. If I am not mistake, your mileage for instance is stored in both places as a backup.

I think you were on the right track and Kbus is the most important thing for you to troubleshoot at this point. You are correct that the EWS is on the Kbus as well. Since the EWS and DME share a rolling code. If you go to start and if they are not synced or “aligned”, your car would refuse to start.

Do you have a multimeter and have you checked if the Kbus is shorted to ground?

[NGAAutoTV]

One more note, If your Kbus is shorted to ground, you’ll have to find what is causing this. Since the Kbus is a single wire running between many modules, you could have a break in that wire causing the short to ground. Or one of the modules on the bus is shorted. I think you already know this as you were looking at the GM5. If you google Kbus troubleshooting, there is a site bmwgm5 that goes into details on how to take the bus junction apart. You can pursue that route by cutting the wire bundle. Or you can just simply unplug each module on the bus until the bus comes back online. And remember; the instrument cluster is the bus master so it has to be on the bus for it to work.

If you get the bus back online and if the car won’t start, you’ll need to figure out which module was shorted and fix that if it’s a critical module like the EWS. However, you might find you need a BMW scanner to resync the rolling code between the DME and EWS to get your car fully started.

[RossBMWZseries]

NGAAUTO thanks so much for breaking this down for me. Electrical wiring is a whole different language for me. I don’t have a multimeter and have never used one. Looked up a few YouTube how-to videos so I’ll go buy one tomorrow and check for continuity on the K bus. I rather try to do this myself for the sole fact that I don’t trust anyone around here, not even the dealership for these type of issues. Shops trust their computers to pinpoint the issue and give a diagnostic right away without even troubleshooting first to confirm their computer is correct.

[pokeybritches]

Go for a multimeter that has an audible continuity test indicator (it beeps when you have continuity). Auto-range adjustment is a nice feature to have as well.

[RossBMWZseries]

UPDATE:
It’s been 3 months now that my Z4 has been sitting in my garage. Dad life has me tired as shit but I’m adapting. Anyway, I started working on the Z again.

Using my Schwaben (Foxwell NT510) scanner, I got fault code 2F44: EWS preventing manipulation

Googled it and found this link;
https://us.autologic.com/news/bmw-mini-fault-code-2f44

My key is less than 3 years old, purchased and programmed at BMW dealer. I did have a few issues with my battery when I tried troubleshooting the K bus months ago so I’m guessing that it somehow unmatched the EWS/CAS from the DME. The link I posted above states that I can align the EWS to the DME using a computer or scanner. My NT510 gives me the option to align it, however, whenever I attempt to do so, I get an error message indicating my car must be ON. Any advice on how I can align the EWS to the DME, or must I really take it in to a shop?

[NGAAutoTV]

Originally Posted by RossBMWZseries

UPDATE:
It’s been 3 months now that my Z4 has been sitting in my garage. Dad life has me tired as shit but I’m adapting. Anyway, I started working on the Z again.

Using my Schwaben (Foxwell NT510) scanner, I got fault code 2F44: EWS preventing manipulation

Googled it and found this link;
https://us.autologic.com/news/bmw-mini-fault-code-2f44

My key is less than 3 years old, purchased and programmed at BMW dealer. I did have a few issues with my battery when I tried troubleshooting the K bus months ago so I’m guessing that it somehow unmatched the EWS/CAS from the DME. The link I posted above states that I can align the EWS to the DME using a computer or scanner. My NT510 gives me the option to align it, however, whenever I attempt to do so, I get an error message indicating my car must be ON. Any advice on how I can align the EWS to the DME, or must I really take it in to a shop?

If you can find someone with ISTA+ and a K+DCAN cable, it can do the alignment for you. It takes only a few minutes.

I have an NT510 and find it useless at times. It won't even auto scan or recognize my F10 535.

[RossBMWZseries]

Originally Posted by NGAAutoTV

If you can find someone with ISTA+ and a K+DCAN cable, it can do the alignment for you. It takes only a few minutes.

I have an NT510 and find it useless at times. It won't even auto scan or recognize my F10 535.

Bummer, I don’t know anyone near me with Those tools, looks like I’ll take it in to the shop.

Yea I noticed the Nt510 didn’t auto scan my brother’s F87 either. I haven’t tried it on my F15 but works great with my E85 and E92. The F chassis probably needs something more up to date

Thanks for all your help though! Looks like I may have to invest in ISTA+

[RossBMWZseries]

UPDATE:

Z4 hasn't started since 06/30/19. I took it to a local indy shop on 10/21/19 and it's been there since. Not much has been done to it other than sitting outside their garage. They told me the EWS needs to be synched to the DME. The owner of the shop stated he has a buddy that has an E85 Z4 and was going to bring in his car so he could download the software and allow my car to finish the download. If what I said doesn't make sense, that's because I probably said it wrong and don't recall his words exactly lol). This buddy of his never showed up and it's been about 4 weeks of waiting for him. I suggested I should just buy a new EWS module as they're under $200. The shop owner suggested reaching out to "some guy in florida" that repairs modules. He overnights the modules and within 2-3 days you'll have the module back and it'll be plug and play. Sounds like Scott from the GM5 repair but he's not in Florida. At this point, I want to go the cheaper route and honestly I'm not sure who this guy in Florida even is so buying a new EWS seems like the best option. Any thoughts on this?

I miss my damn car. Weather here is perfect and the Z4 never has to be put away for winter but technically, I now know how some of you guys feel.

[Vanne]

Try this mate.. ignition off and then back on and then use the windows button up. Does it go up at all, even say half an inch? And then it stops automatically? Edit: those 2 earth blocks on the pax side in my car are in the side wall, a tad bit higher than your feet level.

I've never seen those 2 purple connection blocks..

Edit: soz your feeling like crap mate. :/

[RossBMWZseries]

Originally Posted by Vanne

Try this mate.. ignition off and then back on and then use the windows button up. Does it go up at all, even say half an inch? And then it stops automatically? Edit: those 2 earth blocks on the pax side in my car are in the side wall, a tad bit higher than your feet level.

I've never seen those 2 purple connection blocks..

Edit: soz your feeling like crap mate. :/

Negative Vanne; the car won't start. If you mean "back on" to the on position without the engine actually starting, I'm not sure. The driver's window regulator needs replacement. Passenger window, I believe it goes all the way up.

[Terraphantm]

If it's just an EWS sync issue, you should be able to take care of that yourself in about 30 seconds.

[RossBMWZseries]

Originally Posted by Terraphantm

If it's just an EWS sync issue, you should be able to take care of that yourself in about 30 seconds.

Assuming that I have ISTA+ or Dcan cable? Unfortunately I don’t.

[GuidoK]

But you can get such a cable for about $10 delivered.

[Terraphantm]

Originally Posted by RossBMWZseries

Assuming that I have ISTA+ or Dcan cable? Unfortunately I don’t.

So get them? Consider it the same as buying a somewhat specialty tool (e.g a torque wrench) to make some DIYs possible.

And technically you don’t need ista either, inpa is sufficient for this.

[RossBMWZseries]

You guys are right, however, the issue is that the car’s computer apparently can’t be read. Whenever they try to synch the EWS to the DME, the download stops. That’s the reason he wanted to bring in his buddy with the Z4; to download his software and allow it to finish downloading in my car. Again, I apologize if im not making sense. This is something I hardly understand.

[Terraphantm]

Originally Posted by RossBMWZseries

You guys are right, however, the issue is that the car’s computer apparently can’t be read. Whenever they try to synch the EWS to the DME, the download stops. That’s the reason he wanted to bring in his buddy with the Z4; to download his software and allow it to finish downloading in my car. Again, I apologize if im not making sense. This is something I hardly understand.

The fact that the shop is talking about downloading things from a car tells me they have no clue what they're doing. Another Z4 will not aid in the process in any way whatsoever.

Most likely they just need to bridge pins 7 and 8 on the obdii dongle. Less likely but still plausible scenario is that the EWS module is actually dead or something is pulling the K-bus down.

[Vanne]

Ross, I have two of those cables mate, could send you one if you like. consider it a late Chrissy pressie.

[RossBMWZseries]

The shop owner used to work at my local BMW dealer, he was there for over 15 years that I know of. He was the only ONE person at the dealer that I actually trusted, which is the reason why I brought my car to his shop. I've talked to a few BMW "savvy" guys and they've stated that this process is not unheard of and the success rate of downloading software into another car of the same chassis is pretty high. Then again, I've never heard of it myself.

I appreciate the kind gesture Vanne! Unfortunately my laptop stopped working and don't have access to one. My understanding is the laptop would be required to use these cables.