[vilord]

Does the rear glass also open when locked?

Another option would be to just unplug the wire that goes to the tailgate handle, and always open the tailgate with the remote button.
Annoying, but at least you wouldn't be leaving the boot unlocked everywhere.

[gbalthrop]

Originally Posted by Tambohamilton

...At this point, I don't really know what to do. I can't find anything wrong with the latch

If the latch locks when voltage supplied to Pin #4 with #3 grounded, then that's OK, and as you say, all the other JBE functions work, INCLUDING the Rear Window Lock/Unlock IIRC? My SWAG is that BOTH the Hatch and Rear Window "Lock" by simply defeating operation of the "Buttons" that send a signal to the JBE to "Unlatch" the respective latch. In other words, the Unlatch circuit is simply made "Open-circuit" so it does NOT operate when "locked." If that interpretation of the schematic is incorrect, Please Enlighten me.

That suggests there is something weird in the wiring to the Hatch Latch Connector X311, either the Gray/Brown wire (Input to JBE) at Pin#2, or the Gray/Green wire (Output from JBE) at Pin #4. The Ground at Pin #3 has no moving parts, and the Cargo area lights function when that ground is completed to Pin #1, so there has GOT to be something weird happening at Pin #2 OR #4.

I know you have covered this at least once in the 67 posts in this thread , but IF the Rear Window Locks/Unlocks as it should, WHY NOT compare the Voltage & Continuity to ground readings at Connector X311 for the Hatch Latch to those for comparable Pins at the Rear Window Lock Connector, X13059? The pins are the SAME EXCEPT functions of Pins 1 & 2 are SWAPPED between the otherwise similar-electrically (at least according to the TIS schematic) locks.

Your 8V and now 12 to 0 Voltage readings at Pins #4 & #2 CANNOT be the way it is SUPPOSED to work. My swag is that there is a wiring fault in either (A) the Gray/Green wire at Pin #4, or (B) the Gray/Brown wire at Pin #2, both of Connector X311. Keep in mind that BOTH "Latches" (Hatch & Window) are UNlatched electrically by buttons whose inputs to the JBE can be tested using INPA or such. Have you tested for continuity in the Gray/Green wire between Pin #4 of X311 and Pin #12 of Connector X14270 at the JBE? Also tested for short to chassis ground, BOTH while raising/lowering the tailgate?

ANYONE know what the German Abbreviations/ Acronyms "MERHK" and "MERHS" mean? More specifically, what is "MER" a German abbreviation/ Acronym of? HK almost certainly stands for HeckKlappe or tailgate, and HS for Heckscheibe or Rear Window. So WHAT does the MER prefix stand for? Likewise the "TOE" and "K" in the "Central Locking Inputs" Schematic, related to HeckKlappe & HeckScheibe.

ANYONE know of any reference that gives German Abbreviations/Acronyms as used by BMW? What about electronics symbols as used in the TIS schematics. Those things are PACKED with information and 50%+ of it goes over my head 'cuz I ONLY know the basic symbols and conventions that are listed in Bentley.

Just so everyone can "play along at home" I attach the pertinent TIS schematics for Late 2007 E91 (used OP's VIN) for Central Locking Outputs, Inputs, & Interior Lights:
https://www.newtis.info/tisv2/a/en/e...tlputs/dWHzxgC
https://www.newtis.info/tisv2/a/en/e...inputs/dPBLOhG
https://www.newtis.info/tisv2/a/en/e...ghting/r6lwiWv

Thanks,
George

[Tambohamilton]

Originally Posted by vilord

Does the rear glass also open when locked?

Another option would be to just unplug the wire that goes to the tailgate handle, and always open the tailgate with the remote button.
Annoying, but at least you wouldn't be leaving the boot unlocked everywhere.

Yeah, I agree that the JBBF is looking most suspect at this point. I'd like to know too about the comms between JBBF and CAS. I really hope it's not a bad CAS!

I guess with replacing the JBBF I just need to get the right hardware (correct part no), then default code and all should be golden?

Yeah, I could disconnect the button, or install a valet switch in the latch actuator line from the JBBF, but I'd really prefer to fix it properly at this point.

Good question on the glass...I'm 90% sure it functions correctly (actually 'locks'). I'll check tomorrow though.

Thanks for the help

[Tambohamilton]

Originally Posted by gbalthrop

If the latch locks when voltage supplied to Pin #4 with #3 grounded, then that's OK, and as you say, all the other JBE functions work, INCLUDING the Rear Window Lock/Unlock IIRC? My SWAG is that BOTH the Hatch and Rear Window "Lock" by simply defeating operation of the "Buttons" that send a signal to the JBE to "Unlatch" the respective latch. In other words, the Unlatch circuit is simply made "Open-circuit" so it does NOT operate when "locked." If that interpretation of the schematic is incorrect, Please Enlighten me.

That suggests there is something weird in the wiring to the Hatch Latch Connector X311, either the Gray/Brown wire (Input to JBE) at Pin#2, or the Gray/Green wire (Output from JBE) at Pin #4. The Ground at Pin #3 has no moving parts, and the Cargo area lights function when that ground is completed to Pin #1, so there has GOT to be something weird happening at Pin #2 OR #4.

I know you have covered this at least once in the 67 posts in this thread , but IF the Rear Window Locks/Unlocks as it should, WHY NOT compare the Voltage & Continuity to ground readings at Connector X311 for the Hatch Latch to those for comparable Pins at the Rear Window Lock Connector, X13059? The pins are the SAME EXCEPT functions of Pins 1 & 2 are SWAPPED between the otherwise similar-electrically (at least according to the TIS schematic) locks.

Your 8V and now 12 to 0 Voltage readings at Pins #4 & #2 CANNOT be the way it is SUPPOSED to work. My swag is that there is a wiring fault in either (A) the Gray/Green wire at Pin #4, or (B) the Gray/Brown wire at Pin #2, both of Connector X311. Keep in mind that BOTH "Latches" (Hatch & Window) are UNlatched electrically by buttons whose inputs to the JBE can be tested using INPA or such. Have you tested for continuity in the Gray/Green wire between Pin #4 of X311 and Pin #12 of Connector X14270 at the JBE? Also tested for short to chassis ground, BOTH while raising/lowering the tailgate?

The latch mechanism doesn't lock, neither mechanically, nor electrically (within itself). It 'locks' when the JBBF doesn't send power to pin 4 to activate the latch motor which releases the tailgate. The 'locking" function is entirely electronic, and entirely within the CAS and/or JBBF. The latch only connects the interior lights to ground when open (pins 1 and 3 bridged when open), the JBBF to ground when closed (pins 2 and 3 bridged when closed), and releases when the JBBF energises its motor on pin 4 (with ground again at pin 3). Between them the JBBF and CAS communicate when the car has been locked, and in this state the JBBF should not energise the latch motor to release the latch. Does that align with your understanding of things?

Yep, vilord has just pointed out that the glass should give clues as to what's going on, since it operates the same way. Thanks for clarifying! Definitely something for me to look into there.

I've tested for continuity between 2@X311 and 11(?)@JBBF; all good. But I haven't tested between 4 and 12. Now, I know that both of these are good enough, because I never get the 'tailgate open' warning bongs/alert when driving unless the tailgate is actually open (wire between 2 and 11 is good). And the tailgate never releases randomly, and it actuates for (at least approximately) the 0.7s specified in the CAS coding when commanded; definitely JBBF signal releasing the latch, therefore 4-12 is good. I know the tailgate hinge wiring is good because I replaced all of it recently.

I'll certainly see if I can glean anything from the glass latch wiring/function when I get a chance. But right now I think the options are to replace the latch mechanism which seems to function perfectly, or replace the JBBF, which seems a little screwy but generally doesn't seem to be in a bad state.. After that I think the CAS would be the next target for replacement, but it's a pain to do the necessary coding etc.

Thanks guys for your help!

[Tambohamilton]

Just checked the glass today, and it functions as it should (actually locks, and opens when the button is pressed). When I get some more time I'll disconnect it, and see how the pins measure.

[dmcbrit]

I have almost the reverse problem with the tailgate and window on my 2008 E91 325d. The back window unlocks every time the engine is started. This is driving me mad. And while the window opens, the tailgate proper won't open at all. When the engine is turned off and the key taken out goes everything back to normal. All the other doors are working normally with the key and the internal central locking button with engine on or off. Does anyone have any ideas how to fix this?

[quigger]

Hey dmcbrit,

I had exactly the same problem on my 2009 e91 320d. I replaced the back window button grab handle and all is well ever since.

See:
https://www.e90post.com/forums/showt...php?p=25644804

Cheers,
Jason.

[Tambohamilton]

Minor development today; I checked for codes when checking out the current beta version of Protool, and it came up with the following error:

JBBF [JBBF87] | A6E2: Central-locking drive, rear lid

This is the first error I've seen related to the tailgate, but I'm not really sure what that means... Maybe/hopefully it just means the latch mechanism is what's been causing problems all along, and it's just getting to the next stage of broken.

Haven't had time to think about it any further yet, so no further progress just now...

If anyone has further insight into the A6E2 code, that would be much appreciated!

[Vut]

I don't have comfort access, but I had a similar problem.

What solved it for me was:
Wrapping electrical tape around the metal hook (upside down "U" shape) inside the car floor/bumper area that the trunk latch locks on. I did a 2 or three layers and it's been like that with no problems for 4 years now.

Simple cheap fix worth a try.

[Tambohamilton]

Cool, I'll definitely try that before spending money on parts... Unless I find something else definitely broken.

[gbalthrop]

Originally Posted by Tambohamilton

Minor development today; I checked for codes... and it came up with the following error: JBBF [JBBF87] | A6E2: Central-locking drive, rear lid
... I'm not really sure what that means...

That truly is a MINOR development: I think it means "Your Tailgate Won't Lock", but then I believe you had ALREADY determined that.

I have difficulty with proper concept of that system from the TIS Schematics.
My recollection is that "Locking" the Tailgate actually is simply "Defeating" or "Electrically-Disconnecting" the "UNLATCH" button to prevent it from ALWAYS unlatching the tailgate when the exterior button is pressed. If that is the case, then the latch and its button above the license plate work fine. TOO FINE, as in you CANNOT turn the Darn Thing OFF, or open the UNlatch button circuit.

My recollection is that we've had this discussion before, and ONE of us (perhaps/ likely ME ;-) didn't understand the other's concept. Did you ever compare the inputs/outputs between the Rear Window Latch and the Tailgate Latch, along with their respective "Buttons"?

I'm DEFINITELY confused, about what can cause your issue, or how to test it, and I'm NOT inclined to take apart my system to test & try to educate myself, so if you get this sorted, please enlighten the REST of us.

Lazy George

[Tambohamilton]

Originally Posted by gbalthrop

That truly is a MINOR development: I think it means "Your Tailgate Won't Lock", but then I believe you had ALREADY determined that.

I have difficulty with proper concept of that system from the TIS Schematics.
My recollection is that "Locking" the Tailgate actually is simply "Defeating" or "Electrically-Disconnecting" the "UNLATCH" button to prevent it from ALWAYS unlatching the tailgate when the exterior button is pressed. If that is the case, then the latch and its button above the license plate work fine. TOO FINE, as in you CANNOT turn the Darn Thing OFF, or open the UNlatch button circuit.

My recollection is that we've had this discussion before, and ONE of us (perhaps/ likely ME ;-) didn't understand the other's concept. Did you ever compare the inputs/outputs between the Rear Window Latch and the Tailgate Latch, along with their respective "Buttons"?

I'm DEFINITELY confused, about what can cause your issue, or how to test it, and I'm NOT inclined to take apart my system to test & try to educate myself, so if you get this sorted, please enlighten the REST of us.

Lazy George

George, I 100% agree. The reason that this is a development at all is that it's the first time my car has agreed with me that there is a problem (except the alarm, which sounds when I open the tailgate with the car locked )

Yes, what you've written here is exactly how I understand the logic of the tailgate latch. And yes, it's working far too well!

I haven't yet had time to look at the mechanism/wiring for the tailgate glass...I'll get to I when I can. I want to inspect the condition of that switch too, since it seems to be a common instigator of weird tailgate behaviours.

one day I'll get this figured out and post up the solution here...

[gbalthrop]

Originally Posted by Tambohamilton

... one day I'll get this figured out and post up the solution here...

I'm a sucker for "puzzles".

So here's my conclusion and my rationale (based SOLELY on interpretation of TIS Schematics, and NO actual testing on my 3/2007 E91):

Conclusion:
1) There is a faulty "Ground" signal via the Gray/Brown wire from Pin #2 of the Tailgate Latch Connector, X311 4-pin connector, to pin #11 of Connector X14271 at the JBE. Most likely cause of such a faulty ground signal is broken wire (Gray/Brown wire) at hinge plane, particularly if you open close tailgate frequently. OR
2) There is a fault in the JBE itself where "Lock" actuation locks/disables ALL other latches, including Rear Window Release Button, but NOT the Tailgate Latch Release Button (unlikely).

Rationale, based upon function of EACH of four (4) X311 wires:

1) White/Brown wire at Pin #1 completes a GROUND to the Cargo Area Lights, when the Tailgate LATCH is OPEN. This TIS Schematic shows the Latch CLOSED, and NO ground supplied to the lights. Your lights work, so latch is completing that ground for Cargo Lights when latch is OPEN:
https://www.newtis.info/tisv2/a/en/e...ghting/r6lwiWv

2) Gray/Brown INPUT of Ground signal from Pin #2 of Tailgate Latch to Pin #11 of X14271 at JBE. ONLY function I can see that Gray Brown wire serving is to tell JBE that latch is CLOSED as shown in Central Locking INPUTS Schematic below. Apparently the Tailgate Latch Release Button CANNOT be defeated unless that ground signal is present (latch is closed). So if that Gray/Brown wire is broken or disconnected anywhere between the latch and X14271 at the JBE, then the hinge plane flex point is the first suspect.
https://www.newtis.info/tisv2/a/en/e...inputs/dPBLOhG

3) Brown wire at Pin #3 is the Chassis Ground for ALL 3 purposes: a) Cargo Light Ground, b) latch signal to JBE, and c) motor/solenoid ground. We know that's OK, as the Latch UNlatches, and the Cargo Lights work.

4) Gray/Green wire at Pin #4 is the "UNLATCH" voltage signal from the JBE to the Latch Motor/Solenoid. We know that works (along with the Boot Lid Button, S172a) 'cuz the thing ALWAYS unlatches. Here is the TIS "Central Locking Drives" or Outputs Schematic showing that Gray/Green Wire to Pin #4 powering or actuating the Motor/Solenoid:
https://www.newtis.info/tisv2/a/en/e...tlputs/dWHzxgC

If you had INPA, I could show you how to use that to test functions of the "ZV" Locking/Unlocking Relays, the Tailgate Latch and the Rear Window Latch and Unlatch Buttons. I'm NOT sure there is a good way to test integrity of the Gray/Brown wire however. Although you COULD disconnect X14271 at the JBE and use test wire and a multimeter to test continuity, I would suggest simply sliding the rubber gaiter back on the wiring at the hinge plane and inspecting the Brown/Green wire from Pin #2 of X311.

ANYONE know which side that wire runs on?

It would probably be wise for all of us (myself included ;-) who have E91 models 10+ years-old, to inspect the condition of those wires, just so we know what we'll have to deal with soon, particularly if we use the tailgate a LOT in cold weather.

George

[Tambohamilton]

George,

I replaced all of the wiring in the hinge a couple of months ago, and it didn't help. All wires from the body to the tailgate go through the RH (US passenger) side, unless I completely missed some at the LH side. The symptoms didn't change when I replaced the wires. Some had cracked, but I'd previously repaired them and all the repairs were still OK looking. Thus error code is a more recent development.

I agree with your diagnosis, but I think there's something slightly weirder going on, because last time I tested there was weird behaviour at the X311 connector...especially on pin 2. See post #65. To me that either points a finger at the JBBF, or it's behaving strangely due to erroneous input from something else (glass button, etc).

The real strange thing is;
1. Interior lights function as they should (pin 1 works).
2. I get the tailgate open warning if I drive with it not fully latched, but it goes away when properly closed (pin 2 seems to work). I also tested the pin 2 wire for continuity to the JBBF; tested good.
3. The alarm sounds if I open the tailgate with the car locked (again, pin 2 is good).

So that really makes it look as if the JBBF module isn't working properly, or maybe the CAS (depending on what it's communication with the JBBF is when there is an open request but the car should be locked).

I really don't think there's much else that can be gleaned from sitting and pondering it - I need to get out there and test/replace/check things. I just have very little time, and not enough money to start throwing parts at it. Of course, if somebody has answers, I'm all ears!

[Tambohamilton]

Another minor update:

A cheap tailgate latch with the newer part number/revision (51247308844) came up on eBay, so I bought it and installed it even though I didn't really believe it would help....and it didn't; same symptoms as before.

[Tambohamilton]

Next update...

Still no progress on function, but I've done a bunch more poking around and testing.

I checked the handle/switch for the tailgate; perfect function. Infinite resistance when sitting, 0 resistance when pressed. Switch looked nice and clean.

I checked the connections at the latch for the glass; it seemed exactly as I expected from the wiring diagrams. The latch functions are essentially identical to the main tailgate one, so that validated the conclusions I'd come to there. Testing the connector, there was nothing weird going on, like there is at the tailgate latch.

I also tested the glass switch. This maybe didn't seem ideal, but also seemed functional; it has infinite resistance when sitting, but ~30ohm resistance when pressed. I figure that should really be more like 0 resistance when pressed, but seeing as it's working as it is, I don't think it should be causing any knock-on issues.

I've been getting intermittent madness from the FRM module; it freaks out when the car is left in the sun after rain (perfect for this time of year, in the UK!). It did it the other day, so I got straight in there and removed the FRM. It seemed to be bone dry. I poked around under the carpet, and there was definite moisture, so I went in search of a leak. The only thing I could find was that the seal for the centre-most wiper pivot wasn't seated in the plastic that runs along the bottom of the windscreen. I don't know where any water running through there would end up really, but I figure that if it's getting into the driver foot well, it's quite possibly getting into the passenger one too. My car had a super squeaky demister fan when I got it too, so there's been moisture around there for sure. So...I'm really starting to think that my JBBF has got wet and is now junk.

Sorry for the novel. Any suggestions welcome!

Oh, I bought a used tailgate handle/switch off eBay before looking at mine...it came up super cheap. But mine turned out to be in marginally better cosmetic shape so I didn't fit it. So if anyone, especially this side of the pond, needs one £5 + shipping and it's yours...as soon as I'm allowed out of my house (8 days time).

[vilord]

Water leaking in around the bottom of the windscreen and getting on the fuse box and/or JBBF is actually a relatively common complaint with our cars. Sounds like you might have figured things out!

I take it your diversity antenna is definitely not wet? When my car gets water on the diversity it screws up the locks

[Tambohamilton]

Yeah, so I'm seeing now.

The diversity module is definitely dry, yeah.

[Tambohamilton]

Fixed it!

Thinking my JBBF was faulty, maybe water damaged, I decided I could do no harm by updating it, and default coding. I'd tried default coding previously using Bimmergeeks Protool, but it didn't help. This time, I used WinKFP to update the module (seemingly it was already at the latest version, but I programmed it anyhow), then NCSexpert to default code it. Then cleared the errors using INPA (had to cycle the ignition for them to all go away). And now the tailgate locks!

In the end I repaired the tailgate wiring at the hinge (definitely were some damaged wires, but this didn't help), and replaced the tailgate latch (old one seemed to be functioning correctly, but replaced it since I didn't know what else to try). Everything else seemed fine, except some weird signals from the JBBF, measured at the tailgate latch.

So if you're seeing this issue, I would recommend:
1. Check the wiring at the tailgate hinge. If repair is needed, you could also take this opportunity to check the tailgate latch and continuity from there to the JBBF. Newtis.info for wiring diagrams.
2. Default code the JBBF using NCSexpert (not Protool, Carly, etc).
3. Program/update the JBBF using WinKFP, then default code using NCSexpert. I did this using a high-quality DCAN cable with a smart charger attached (my battery is quite old). It only took a couple of minutes.

If none of that helps, further troubleshooting is necessary - this thread has some great info and suggestions from other members.

Thanks everyone for your help!

[rt7085]

Funny. M5 E60 had the same issue with wires at the trunk hinge.

[unrulyteach]

Originally Posted by Tambohamilton

Fixed it!

Thinking my JBBF was faulty, maybe water damaged, I decided I could do no harm by updating it, and default coding. I'd tried default coding previously using Bimmergeeks Protool, but it didn't help. This time, I used WinKFP to update the module (seemingly it was already at the latest version, but I programmed it anyhow), then NCSexpert to default code it. Then cleared the errors using INPA (had to cycle the ignition for them to all go away). And now the tailgate locks!

I'm the end I repaired the tailgate wiring at the hinge (definitely were some damaged wires, but this didn't help), and replaced the tailgate latch (old one seemed to be functioning correctly, but replaced it since I didn't know what else to try). Everything else seemed fine, except some weird signals from the JBBF, measured at the tailgate latch.

So if you're seeing this issue, I would recommend:
1. Check the wiring at the tailgate hinge. If repair is needed, you could also take this opportunity to check the tailgate latch and continuity from there to the JBBF. Newtis.info for wiring diagrams.
2. Default code the JBBF using NCSexpert (not Protool, Carly, etc).
3. Program/update the JBBF using WinKFP, then default code using NCSexpert. I did this using a high-quality DCAN cable with a smart charger attached (my battery is quite old). It only took a couple of minutes.

If none of that helps, further troubleshooting is necessary - this thread has some great info and suggestions from other members.

Thanks everyone for your help!

U are the real mvp

[stewartps]

Originally Posted by Tambohamilton

Fixed it!

Thinking my JBBF was faulty, maybe water damaged, I decided I could do no harm by updating it, and default coding. I'd tried default coding previously using Bimmergeeks Protool, but it didn't help. This time, I used WinKFP to update the module (seemingly it was already at the latest version, but I programmed it anyhow), then NCSexpert to default code it. Then cleared the errors using INPA (had to cycle the ignition for them to all go away). And now the tailgate locks!

In the end I repaired the tailgate wiring at the hinge (definitely were some damaged wires, but this didn't help), and replaced the tailgate latch (old one seemed to be functioning correctly, but replaced it since I didn't know what else to try). Everything else seemed fine, except some weird signals from the JBBF, measured at the tailgate latch.

So if you're seeing this issue, I would recommend:
1. Check the wiring at the tailgate hinge. If repair is needed, you could also take this opportunity to check the tailgate latch and continuity from there to the JBBF. Newtis.info for wiring diagrams.
2. Default code the JBBF using NCSexpert (not Protool, Carly, etc).
3. Program/update the JBBF using WinKFP, then default code using NCSexpert. I did this using a high-quality DCAN cable with a smart charger attached (my battery is quite old). It only took a couple of minutes.

If none of that helps, further troubleshooting is necessary - this thread has some great info and suggestions from other members.

Thanks everyone for your help!

Hi hope you're well! Sorry to bump this post up,i've been searching for literally months to try find a solution to this issue! I've traced all the wiring back and it's all perfect, i'm now 100% sure it's a coding issue.

My only issue is I can't get my head around NCSExpert in order to default code modules. I don't mind if I loose all the coding features as I can add that back, it's just I'd love for my boot to lock again.

Is there any chance you could give me a hand with the coding side of things? Got all the kit just lack the knowhow!

Thanks so much