[vilord]

Should the tailgate latch make a sound when it locks?

On my wagon, the latch makes no sound when the lock/unlock is pressed.
Pressing the release button near the license plate (or on the key) when the car is unlocked causes the tailgate latch release motor to actuate.
Pressing the release button when the car is locked does nothing at all, unless the comfort access key is nearby, in which case the release button activates the CA system to check for a nearby key, and if one is found, triggers the release motor.

I assumed this was all handled by software on the JBBE or CAS... it doesn't make much sense for the tailgate latch to need to "remember" that the car is locked and ignore the release signal. It makes more sense to just not send the release signal at all.

[vilord]

My understanding of the tailgate latch is that it has 4 pins:

1 - ground to the interior lights in the tailgate (will be grounded when open, so the lights turn on)
2 - ground trigger to the JBBF so the JBBF knows that the tailgate is closed (will be grounded when closed)
3 - ground to body/frame
4 - +12v from JBBF to actuate the release motor

There is no "lock"

So, if the tailgate is opening when the car is locked, then either the JBBF is screwed up and is sending the release when it shouldn't, or if the car is equipped with comfort access, the CA module is messing up and telling the JBBF that a CA key is nearby.

[Tambohamilton]

This was my logic too... If the car is locked the JBE just doesn't (shouldn't!) send the 'open' signal/power to the tailgate actuator. This is the only way that makes any sense to me, since there aren't enough wires (1) between the actuator and JBE for it to send separate 'open' and 'lock' signals. Or rather that one wire is insufficient for the JBE to send constant 12v when locked, and a pulse of 12v to open the tailgate.

It still appears to me that my JBE or CAS is bad. If there was a wiring fault (between the actuator and JBE), or a faulty actuator, there would be the following issue(s):
Tailgate doesn't release/open.
Tailgate interior lights stay on/off.
JBE doesn't know when tailgate is open or closed.

I have none of those issues, unless the warning bongs for driving with the tailgate open are triggered by the tailgate interior light circuit. As it is, everything at the back of the car works...even when it shouldn't! The open signal/power is being sent to the tailgate actuator (for the correct time duration, as set in JBE coding, though I haven't edited that particular setting), when it shouldn't be.

My next step will be to physically check the CAS and JBE modules and their connectors, and perform any wiring checks I can while I'm there. This will have to wait until next week.

Just realised that I should have watched the voltage between pins 3 & 4 of the tailgate actuator connector when the tailgate release button/handle was pressed, while I was checking earlier...bother.

Thanks to everyone for their input so far!

[vilord]

maybe the JBE doesn't know the tailgate is fully closed!

if that ground signal back to the JBE isn't grounded, then the JBE will think the hatch is not fully latched and then it will allow opening it even when locked (for the purpose that if it is only partly closed, you want to open and then fully close it.

so i think you found the problem! the JBE is not getting the closed signal.

that could be a bad latch, or a bad wire running from pin 2 on the latch to the JBE. should be gray/brown, labeled HKK on this diagram where it connects to the JBE:
https://www.newtis.info/tisv2/a/en/e...inputs/dPBLOhG

[Tambohamilton]

Surely if the JBE wasn't getting the closed signal, I'd get the tailgate open warning while driving? That signal is most likely to come from the JBE, not from the tailgate interior light circuit (pin 1)?

It's easy to test...I just need to pull my tailgate apart again.

[vilord]

Originally Posted by Tambohamilton

Surely if the JBE wasn't getting the closed signal, I'd get the tailgate open warning while driving? That signal is most likely to come from the JBE, not from the tailgate interior light circuit (pin 1)?

It's easy to test...I just need to pull my tailgate apart again.

Correct, maybe i misread, I thought above you had said that you were getting the bongs.

[Tambohamilton]

Cool, though I wish that had been the problem! My previous post was a bit rambling...my bad!

[N52bigblock]

Originally Posted by Tambohamilton

Cool, though I wish that had been the problem! My previous post was a bit rambling...my bad!

Just had a closer look at this (been crazy busy with a new baby so don't have much spare time) and there is only one output from the JBE to the actuator, and that is the output that opens it,, the other 3 wires are 2 earths and one signal wire that tells the JBE the tailgate is closed. So yes you are correct, if that pin 4 grey/green wire was bad, the tailgate wouldn't open.

I would still check to see whether the JBE is recognizing the tailgate as being closed. From what you have said it probably is recognizing it but wouldn't hurt to check. The JBE is looking a bit suspect at this point though. Keep us posted.

[Tambohamilton]

Congratulations and good luck with the new arrival! Thanks for taking the time to help me out, amongst all that comes with a new human.

I'll check the next bits after the weekend, since the JBE is buried...

Thanks

[gbalthrop]

Originally Posted by Tambohamilton

Pin 3 ground is good, to the body. Getting 8v between pins 3 and 4, regardless of lock state...

Originally Posted by vilord

Should the tailgate latch make a sound when it locks? On my wagon, the latch makes no sound when the lock/unlock is pressed. Pressing the release button near the license plate (or on the key) when the car is unlocked causes the tailgate latch release motor to actuate.
Pressing the release button when the car is locked does nothing at all...it doesn't make much sense for the tailgate latch to need to "remember" that the car is locked and ignore the release signal. It makes more sense to just not send the release signal at all.

Originally Posted by vilord

My understanding of the tailgate latch is that it has 4 pins:
1 - ground to the interior lights in the tailgate (will be grounded when open, so the lights turn on)
2 - ground trigger to the JBBF so the JBBF knows that the tailgate is closed (will be grounded when closed)
3 - ground to body/frame
4 - +12v from JBBF to actuate the release motor
There is no "lock"...

Originally Posted by Tambohamilton

This was my logic too... If the car is locked the JBE just doesn't (shouldn't!) send the 'open' signal/power to the tailgate actuator. This is the only way that makes any sense to me, since there aren't enough wires (1) between the actuator and JBE for it to send separate 'open' and 'lock' signals. Or rather that one wire is insufficient for the JBE to send constant 12v when locked, and a pulse of 12v to open the tailgate...

Originally Posted by vilord

maybe the JBE doesn't know the tailgate is fully closed!

if that ground signal back to the JBE isn't grounded, then the JBE will think the hatch is not fully latched and then it will allow opening it even when locked (for the purpose that if it is only partly closed, you want to open and then fully close it.

so i think you found the problem! the JBE is not getting the closed signal.

that could be a bad latch, or a bad wire running from pin 2 on the latch to the JBE. should be gray/brown, labeled HKK on this diagram where it connects to the JBE:
https://www.newtis.info/tisv2/a/en/e...inputs/dPBLOhG

Originally Posted by Tambohamilton

Surely if the JBE wasn't getting the closed signal, I'd get the tailgate open warning while driving? That signal is most likely to come from the JBE, not from the tailgate interior light circuit (pin 1)?
It's easy to test...I just need to pull my tailgate apart again.

I did NOT realize how simple the circuit actually is (or I may still be entirely missing the point ;-)

Going back and re-reading the TIS circuit diagrams, I appears to me that since BOTH the Tailgate and Rear Window "LATCH" release buttons are electric, and NOT mechanical, there is NO need to LOCK either one in the OLD sense of the word, like with a deadbolt.

Rather, to prevent use of the latch button, all that is needed is to make it electrically "Disconnected", so that pressing the button has NO effect to open the latch. If you examine the Central Locking INPUTS circuit, you will see the Lock or Latch diagrams suggests that the button function is simply to provide a ground signal to the JBE when pressed, as long as the Latch button is NOT electrically disabled.

The function of the "Lock" is to electrically disable the Latch Button so that no ground signal is sent to JBE. The diagram for BOTH the Rear Window Lock/Latch, and the Tailgate Lock/Latch are the same, both with 4-pin connectors, the only difference being the swapping of functions of pins #1 & #2. Here is the INPUTS circuit:
https://www.newtis.info/tisv2/a/en/e...inputs/dPBLOhG
Here is the Outputs or Locking Drives circuit:
https://www.newtis.info/tisv2/a/en/e...tlputs/dWHzxgC
My earlier suggestion that the position of the Tailgate latch made a difference is totally incorrect as I look at it NOW. BOTH the Tailgate & Rear Window latches simply serve to supply a ground to light the Cargo Area lights (3) when EITHER latch is OPEN, causing the lights (Powered by Terminal 30G) to illuminate. Here is the "Interior Lights" circuit to complete the identification of ALL FOUR (4) pins on the Connectors for the Boot Lid or Tailgate Lock/Latch (X311) and the Rear Window Lock/Latch (X13059). You have to look at ALL THREE diagrams to identify the four wires attached to the connectors:
https://www.newtis.info/tisv2/a/en/e...ghting/uNsyrn3

So the MOST likely cause of Tambohamilton's issue IS the tailgate Lock/Latch in my opinion. There are NO fault codes in JBE or CAS, suggesting module function is OK, and the solenoid in the Lock/Latch is NOT electrically functioning to disconnect "Ground Button" or "UNlocked" normal function of the button above the license plate. The Rear Window Lock/Latch works properly, and since the electrical circuit for the two Locks/Latches is the same, if there were any doubt about proper JBE function, one could test voltage at the two JBE Output wires at Pin #4 of each connector: Gray/Green at X311 Pin #4, and Brown/Red at X13059 Pin #4.

If the Tailgate Latch Loop was improperly adjusted, requiring "slamming" of the tailgate to completely latch so cargo area lights went out, that could have damaged Latch "Internals" over time. If the Lock/Latch is replaced and you have an opportunity to "dissect" the mechanism for analysis, you could find anything from worn or broken contacts to corrosion, etc. If you get to that, please let us know your findings.

I'm NOT sure what the 8V measurement "regardless of lock state" means exactly, so if you have some clarification on exactly when that is present, and if it changes when you press Lock or Unlock on remote or Dash, that might change the picture. Obviously if the Output at Pins #4 of the Window & Lid Latch connectors DIFFER under same Remote Button functions, there MAY be a problem with the wires between Pins #4 & the JBE, at the JBE Connector, or the JBE itself. My own belief is that Modules rarely fail, and Mechanical Components, such as the Latch/Lock Mechanisms, are the FIRST suspects to rule out.

Please let us know what you find,
George

[Tambohamilton]

Thanks George. What I meant was that I measured 8v regardless of whether the car was locked, locking, unlocking, or unlocked. It just sat at 8v. I didn't think at the time to check it when I pressed the open button/switch on the tailgate.

It seems like I should take it apart again, and check that, as well as testing for ground on pins 2 and 3 of the lock actuator itself, with it out of the car (manually open and close the latch).

I'll let you know what I find..

[icon2015]

It is very hard to follow all the discussion, there are a few things you can do to diagnose properly your issue.

1st, you need to know if your locking mechanism works, to do this apply 12 V on pin 4(+) and 3(-), just for 1 ms should be enough(a short touch), if it opens then your tail locking mechanism works. If not then there is your issue, a bad locking mechanism.

2nd, if your tail locking mechanism works, then you need to find if the gray/green wire has continuity from pin 12 JBBF to pin 4 lock drive. If it doesn't, and I bet this is the issue, then you have to open again all your car's back and redo the wires. Also at this stage you should check if pin 3 in the locking drive has continuity with the (-) of the car.

Also, important, when I say that you should apply voltage to the mentioned pins, that involves the fact that the actual pins should be removed from the connector and isolated. The fact that you say that you measured 8V between them at anytime, makes me think that the gray/green wire touches at some point a wire with +12V, and is losing 4 V through bad connection to that wire, this also would make any 12 V applied at another point (like JBBF trying to give the command to open) to transform in 8V and heat (probably).

[vilord]

@icon2015 the problem is that the trunk release button by the license plate works all the time, even when the car is locked.

[unrulyteach]

Originally Posted by vilord

@icon2015 the problem is that the trunk release button by the license plate works all the time, even when the car is locked.

That's basically the issue

[gbalthrop]

Originally Posted by vilord

@icon2015 the problem is that the trunk release button by the license plate works all the time, even when the car is locked.

Originally Posted by unrulyteach

That's basically the issue

AND what "icon2015" is saying is that the REASON the Tailgate can always be opened by the "Trunk Release" handle above the license plate, even when the other four doors, gas filler, & rear window are ALL LOCKED, is that the Tailgate Lock/Latch mechanism is NOT working to "Lock" or electrically disable the Latch, either due to a fault in the Lock/Latch unit, or issue with the wiring between the Latch Connector at pin #4 and the JBE.

What "icon2015" is saying is EXACTLY what some of us have said in other ways in earlier posts (only HE says it more clearly ;-), AND he is offering a definitive test for the Lock/Latch unit. I think he may have misspoken when he said "if it opens then your tail locking mechanism works". IF you just substitute: "if it LOCKS, and the handle above the license plate no longer works, then your tail locking mechanism works", it would seem to me to be a correct description of the way the system is supposed to work, and how to test it.

Important thing is to test by VERY brief application of external 12V+ to Pin #4 (just brush pin with 12V+) of the Lock/Latch with ground to pin #3, Connector DISCONNECTED. You might be able to use a 9V battery to test, but if that doesn't Lock the mechanism and defeat the handle operation, then test with 12V+ supply.

IIRC, OP has ordered a replacement latch unit, and if so, can test both the old & new & definitively prove if there is a fault within the old unit.

Thanks for the test icon2015,
George

[Tambohamilton]

We're going around in circles here.

The tailgate actuator doesn't have the ability to lock; when the car is locked the jbe should not send power to it to open. In this case, I know the jbe is sending the power to it to open (even when the car is locked), because the latch is actuated for the 0.5s set in the jbe, regardless of how long I press the tailgate open button (above the license plate).

What I need to do is find WHY the jbe can/will send the open command even when the car is locked.

It could be a fault in the tailgate latch, not sending the ground signal to jbe when the tailgate is closed. I doubt this though, because I get no 'tailgate open' warning when driving, and the alarm will sound when opening the tailgate with the car locked. I will check it though, since these functions could be fulfilled by the lighting ground switch.

There could be a wiring fault between the latch and jbe. The jbe could be faulty. Depending on what signals are passed between the jbe and cas, the cas module could be faulty. What I do know though, is that the latch responds properly to power input (opens), and the lighting ground switch works, and that the open command comes from the jbe even when the car is locked.

The constant 8v at the tailgate latch connector is fishy, and needs to be investigated.

Thanks to everyone for their help. I'm now a lot clearer on what I need to test.

[unrulyteach]

Originally Posted by Tambohamilton

We're going around in circles here.

The tailgate actuator doesn't have the ability to lock; when the car is locked the jbe should not send power to it to open. In this case, I know the jbe is sending the power to it to open (even when the car is locked), because the latch is actuated for the 0.5s set in the jbe, regardless of how long I press the tailgate open button (above the license plate).

What I need to do is find WHY the jbe can/will send the open command even when the car is locked.

It could be a fault in the tailgate latch, not sending the ground signal to jbe when the tailgate is closed. I doubt this though, because I get no 'tailgate open' warning when driving, and the alarm will sound when opening the tailgate with the car locked. I will check it though, since these functions could be fulfilled by the lighting ground switch.

There could be a wiring fault between the latch and jbe. The jbe could be faulty. Depending on what signals are passed between the jbe and cas, the cas module could be faulty. What I do know though, is that the latch responds properly to power input (opens), and the lighting ground switch works, and that the open command comes from the jbe even when the car is locked.

The constant 8v at the tailgate latch connector is fishy, and needs to be investigated.

Thanks to everyone for their help. I'm now a lot clearer on what I need to test.

I replaced push button and lock actuator to avail

[icon2015]

Originally Posted by vilord

@icon2015 the problem is that the trunk release button by the license plate works all the time, even when the car is locked.

Sorry, I have misread, I thought that the trunk wont open.

Then..., to properly diagnose this, remove the trunk release button, and after, check if pin 1 (grey/yellow) has continuity to the (-) if it does then you have to check the wires in the back of the car(top right side as you look at the back) that wire probably touches the chassis or the (-) wire(brown).

To be sure that the JBBF is not broken, just remove pin 44 (grey/yellow) from X14271 connector (the blue one). After this, you or the car shouldn't be able to open the trunk with the rear button. If it still opens by itself, then indeed it is the JBBF that is bad.

I have never seen a JBBF broken in this way, and I have seen a few.

IMO the issue is at some broken wires.

Good to know:

- the trunk release button it is a simple switch that sends (-) to JBBF, which is translated as a +12 signal to the trunk release actuator
- the signal that informs the car that the trunk is opened or closed is delivered by the grey/brown wire, which if it receives (-) signal then the car knows the trunk is opened, otherwise it thinks it is closed

[Tambohamilton]

Good info there, thanks!

Just curious; have you seen (m)any e9x with this problem before (tailgate can be opened with the car locked)?

[icon2015]

The issue is reported mostly at E91 and E61(almost all will face this issue with the broken wires), and in 99.99% of the cases the broken wires are to be blamed. Sometimes you have to open/disassemble the full back of the car to the chassis to properly solve it.

[Tambohamilton]

OK, checked the latch mechanism, and it works as expected (pins earthing when expected, etc). I'm 100% certain that this isn't the issue now.

I checked continuity between pin 2 at the latch and pin 11 at the jbbf; all good.

Still got the same issue, where the tailgate is never locked (but behaves properly otherwise).

Default coded the cas using protool - came back with the same weird settings (petrol, 6cyl, v8, 8spd manual, etc).

I do have inpa/ista/etc etc, though not really clued up on using them.

I haven't checked the wiring above the rear headliner, but I do have a harness repair set on order, which I'll hopefully fit in the next week or 2.

Any further suggestions?

[vilord]

You could maybe use WinKFP or ISTA/P to flash the program and data to the JBBF and/or CAS, perhaps... ISTA/P is "easier", but is exceedingly slow, processor intensive, and requires some giant database file downloads that you may not yet have.

You can probably find a tutorial for winkfp with a little searching. Winkfp might also let you re-install the same software version you already have, in case it somehow got corrupted in the flash memory.