Erroneous messages multifunction display Citroën XM

[Jarvis_C]

Hello,

I am writing this query to see if anyone can offer solution on this problem. It is a Citroën XM 2.1 TD, (if you have seen my presentation and something does not fit you, today I have two, yes hehe). Well, the fact is that the multifunction screen failed when I acquired it, (the one on the left of the steering wheel and that offers messages and information about the car), it is an endemic evil and it was the typical problem: the pixel stripes are erased and it can not be read. So I took the dashboard apart to see if I could change it and soon it stopped working, although this seems irrelevant. Well, I got a scrapyard, I plugged it in and it reads fine, all correct, but the messages that appear are wrong. All the time they are interspersed "front right door open" and "right rear door open" being all closed, and if I open a door on the left, the tailgate, or the bonnet, it says nothing about it, continues with the front right and the back right. Apart from this, when said screen is connected, two lights light up on the central panel, the one for the windshield washer fluid, (the level in the reservoir is full), and the one for the coolant, (the level is also correct and the sensors were cleaned, the The temperature of the engine running is also correct and does not change), in addition to the stop light that accompanies this second, it also comes on. If the information display is switched off, these lights do not come on.

I bought a second screen, (in the other XM I have the same problem, -the one that cannot be read-, and I need to change it too), and incidentally since I have it disassembled, I checked in this car if the problem was the screen , and it turns out that it behaves exactly the same way, it connects and the wrong messages from the doors appear. So the problem is not on the screen, I tried to disconnect the battery for a few hours, etc., and the messages remain. Right now I cannot recover the correct functioning of the screen and to put the messages that it has to put, and for the witnesses that appear erroneously to disappear, I have to disconnect it or put the old one that does not work.

I do not understand electronics / electricity and I do not know if it is a problem of control units, connections, if a lexia type program is needed to erase faults or reset, if this is possible, or how the matter works. I would like to correct the problem and have it work fine as I have managed to find the replacement screen which is difficult.

Excuse me if I have lengthened the message a lot, it is so that it is well understood. Regards!

[Dieselman]

Your description of the car with pixilated left screen sounds like the car is a Series 2 car.
Are the new screens from a Series 2, or Series 1, car?
The screens are different between the two versions and wiring changes to different pins.

There is no coding or control unit, the wiring goes from each sensor, or contact, to the warning lights panel and the left display.

Check the displays are correct, check the warning lamps panel is Ok, download the wiring diagram and check the signals. Page 36/116.

http://www.club-xm.co.uk/forum/downloa ... hp?id=7919

[Jarvis_C]

Your description of the car with pixilated left screen sounds like the car is a Series 2 car.
Are the new screens from a Series 2, or Series 1, car?
The screens are different between the two versions and wiring changes to different pins.

There is no coding or control unit, the wiring goes from each sensor, or contact, to the warning lights panel and the left display.

Check the displays are correct, check the warning lamps panel is Ok, download the wiring diagram and check the signals. Page 36/116.

http://www.club-xm.co.uk/forum/downloa ... hp?id=7919

Thank you very much for the reply! Well, this car, the 2.1 TD, is a bit special, it is a phase 1 of the year 91 to which the engine and electrical system were changed for those of phase 2, and it also has the complete interior of a phase 2 so that, in theory, the screens, which are from phase 2, should be valid, but here, following the comments, I have noticed something that I had not given greater importance to. The screen I had on has a paper sticker with reference 96 178 159 80, and the ones I bought that appeared as phase 2 in the ads have an engraving with reference 96 015 876 ​​80. I thought about their appearance and when I saw the " plug "and wiring that was a simple renumbering. So the first one is from a phase 1 and the others from phase 2? Could the rest of the electrical systems have been changed and not this? (the latter is already out of curiosity).

The truth is that with the one that is damaged, the messages cannot be read but, when opening a door, for example, the beep sounds that warns, that is, it seems to react, and on the other hand, the witnesses with the wrong signals disappear center box. This tells me that I will have to find a phase 1 one to test, or leave it as it is for the moment because it does not affect the operation of the car, although I would not like this. In the video it seems that what is done is cleaning the contacts and adds a plastic at a given moment. In principle, on the screen in question, it seems that the flat cable that connects the part of the circuit with the glass, and it is what usually causes problems, is well visible, so I will try to do that cleaning first to see what happens.

[Jarvis_C]

By the way, I wrote to the administrator because I was wrong to open this topic to see if he can move it, because I think it should be in the Electricity section but he has not answered me yet.

[xmexclusive]

Do not assume that phase 1 and phase 2 are the only differences with these displays.
There and at least 6 different part numbers for these displays and we do not have a definitive list for their specific use.
The wiring difference between phase 1 and phase 2 has already been mentioned and this is the only wiring change.
It was done to allocate a pair of serial signal wires for the XM Phillips radio and matching CD usage text to the LH dash display.
These displays had a major component change with the LCD used thought to have taken place in 1996.
That change included a totally different connector between the displays and the printed circuit board.
The repair instructions using the expensive replacement conductive rubber strip can be found on this website.
These instructions APPLY ONLY to 1996 and LATER displays.
The earlier displays all use a much simpler pair of thin connecting strips fitted to each side of the LCD glass.
Each of these strips pass the same set of signal contacts.
It is this duplication of signals sent that is the main reason these displays are much more reliable that the later ones.
Refurbishing the duplicated signal displays just needs the thin contact strips cleaned.
I think it is important that those contact strips are not rotated but go back in the same way round.
Some years ago I wrote up details about the display types and part codes that had been identified.
No idea where to find that now, sorry.
A quick look on the bench here has turned up 5 complete displays.
96 015 876 80, 96 156 259 80, 96 178 159 80 & 96 319 033 80.
None of these has been taken to bits.
I will see if I can test them in a phase 2 car tomorrow.

[xmexclusive]

Sorry should have told you that there is no problem with this post staying here.
If someone is interested enough to pull together a definitive piece on LH displays it will get put into the self help section.

I was probably wrong above in saying that only one wiring change happened with these displays.
I forgot about the LANGUAGE changes.
There were at least 4 of these.
Fuses on the main fuse board are used as on/off links to select displayed language.
The selection wires were allocated with the initial display but not all used initially.
The fuse board was altered somewhere around 1996 to add a battery protection shunt.
Think I summarised the language link options a couple of years ago.

[White Exec]

If the conversion of the interior to Phase 2 does NOT apply to the dashboard and instruments, then (hopefully) it's likely that the dash wiring is still Ph.1. In which case, you should probably do any testing with a Ph.1 LH (matrix) display.

[Jarvis_C]

I think that this topic would be more appropriate to be in its corresponding section of electricity. I put it by mistake in "members cars" because it was the first post I published.

[Jarvis_C]

Thanks again for the answers. I continue with the investigations of the dot matrix. I have tried unsuccessfully to fix the one that came with the car and that marks well but cannot be read. I have completely disassembled it, I have cleaned everything well with contact cleaner, I have tried several times adjusting here and there, and I have not achieved anything, well, if I lose more pixels.

I have been seeing that on the internet there are different "kits" that they sell to fix the screen, but I do not know if they will be really effective and how it is carried out. They are going the way of replacing the flat cable that connects the circuit with the glass, in some it says that it is "without glue". What I have seen is that the conductive rubber could be the cause, but, although it is a little crushed, in principle it seems to me that it is fine.

As for differences with the other matrices that I have as spare if there are any, apart from the reference I have already seen other things.

The connector that is in the car has three pins without cable, the three central ones and I have managed to confirm that the damaged dot matrix as corresponds to the rest of the installation is series 2. Another piece of information, I made an express visit to the scrapyard and saw a connector in a series 1 and this one did have all the pins with cable, which surprised me. Apart from depending on the series, can the engine or the equipment have an influence on one screen or another?

I have the electrical diagrams but I haven't had time to study them and I'm not very good at them either, let's see if I can give the subject a spin. I'm a bit reluctant to get to touch the wiring because I see it complex. Forgive my ignorance but I don't know exactly how the cables are disassembled on those pins and reconnected.

For now, as in the 2.0 Turbo CT I have the same problem. I am going to disassemble the dashboard, which is not a little, to see if in this case the replacement screen works directly, I hope so.

Greetings.

[Dieselman]

Without checking, I believe the additional cable conenctions for Series 1 left display is for rear lamp failure warnings, which were deleted on Series 2 left displays.
The type of engine has no bearing on the messages in the left display.