Suspension Message On Dot Matrix, What triggers it?

Hi guys,

Hope everyone had a nice Christmas, and an XM fault free new year

Just a minor one this, rather more of a niggle than a problem as such...

Supposedly, the dot matrix is meant to display the suspension state when you startup, and when you turn the sport button on / off. It apparently displays 'Sport suspension / Normal suspension' or similar. I have never seen my S2 do this at all since I got it. Though the hydractuve switch does work I know that much.

Does anyone have the foggiest notion where this data comes from, and how it reaches the dot matrix, or indeed, what I can check in the vein hope of making it work again? Call me an optimist....

Also, come to think of it, the dot matrix is supposed to beep when it displays messages as well? I've never heard it do that either......


Cheers.

Ciarán.

Hi Ciaran

Mine does both and I wish it wouldn't sometimes! only it usualy says "ABS out of use". I cant say for sure but I would expect it to be triggered by the position of the switch itself. It probably either has two sets of contacts or the display senses whether there is a voltage being fed to the computer or not. This information may of course come from the computer itself, the only way to prove that would be to swap it for another one. Not a lot of help really am I! I am sure Noz would have a circuit, if you ask him nicely I'm sure he would look it up for you, or get his CD!

Mine has so many failed pixels that I have to guess what it says anyway, but that 'beep' annoys me!

Peter.N.

Hi Peter,

Not at all, your response is very helpful as usual, and has given me something to think about. I do have an S1 hydractive ECU from my old XM, but that's not going to even fit the connector is it?...let alone work properly

The beep thing has got me wondering actually, is the speaker that makes the beep contained within the dot matrix itself, or is it somewhere else, for example the immobiliser?
Come to think of it, I think I heard it beep once, when I was working on it in a garage, and the battery was extremely low. I tried to start it, and the dot matrix displayed spurious messages like 'Engine temp too hot slow down', 'Warning brake pressure loss' etc etc, and beeped with each one. Also the speedo and rev counter went bananas, but that's another story. Since that it has never beeped to my knowledge.

Hmmm... should be an interesting one to track down.....

Hi Ciaran, Peter and All

The beeper for the dash displat is a Pizo sounder. It is mounted on one of the display pcb's. Seem to remember it is in the clock one but will check when I find those I took to bits.

Regards

XMexc

Hi All

A follow up to the last post. The Piezo sounder is mounted on the Left hand display board not the clock display. In Mk1 and early Mk2's the electronics to drive the LH display contains a memory device that has all the display messages stored in it. Message selection is by separate signal wire hence the large number of connecting wires. Language selection is done by taking 3 of the wires to combinations of positive and negative (some of the fuses in the main fuse box are used to programme this). To complicate matters further the display also accepts serial data on 2 of the wires to display radio/cd messages but I do not think this link can be used to display other used defined messages. There does not seem to be any wire information in the manual let alone circuit diagrams or functional description. In summary a horrendously complicated piece of 1980's electronic junk with serious reliability problems.

Regards

XMexc

Hi all,

I'll add my tuppence worth here.

The LH display does indeed have a piezo 'speaker' for the beeps as xmexc says. It sounds every time the display changes with the exception of the radio display which I'll get to in a second. As xmexc says the unit has a number of pre-programmed messages stored in its eeprom. Each message can be simulated in turn by earthing each if the trigger cables in turn. If you look at the wiring diagram you'll see that the display trigger wires are all wired in series with the associated warning switch or sensor which earth in the fault condition. There is a priority list which I've never really tried to discover. For example an ABS fault will override a 'Door Open' signal etc etc. There's also a link from the alternator for an engine running signal. Without it the alarms are suppressed otherwise when you put the key in the ignition you'd get dozens of alarms.

The exception to this is the 'serial' data which is used to reproduce the radio display. This is transmitted in VAN (Vehicle Area Network) which is a serial protocol. A bunch of guys on a Peugeot forum have cracked the code and can send messages at will to the display. I had high hopes of breaking the code to the engine ecu and having real time engine values or faults displayed on the LH display. The display part is cracked, a PIC chip can be programmed to handle the interface but I fell down at the ecu part. I simply don't have enough electronics background to take it any further. Shame really. It would have been a really nice touch and very simple to implement.

I'm not sure I agree with xmexc's view of the display. From my point of view they are all let down by a really stupid ribbon cable. If someone could come up with a serious fix for this we could all have them working. Personally I like having running data displayed whilst I'm driving. But then I am a bit touched, hence being here.

cheers

noz

ps All my comments are about S2's. I don't have any knowledge of the S1's display

Hi everyone,

Many thanks for the replies folks, much appreciated. So, the buzzer is indeed in the display itself, makes sense.
Now to my next question, am I asking for trouble with regards to dead pixels if I disassemble the display? It currently works perfectly, and it must be one of the few, so while I'd like the beep to work, I really don't want to wreck the display in the process.....

That's very interesting regarding the cracking of the serial bus on it, Noz. I didn't know pugs had the same display, I assume the 605 does?
Do you have any futher data on this, its something I'd be very interested in.
Thats quite an ambitious plan for displaying runtime data from the various sensors, I'm sure it's not too impossible, I just wish I knew enough about ECUs to assist...
The newer Fords have a test mode (video here for anyone interested) that can display about 30 different values from various sensors etc, I always wanted something like this, sounds like exactly what you had in mind also.

Food for thought anyway!

Yes.

You're a fiddler aren't you? Leave it alone & live with the lack of bleeping.

Well Wirdy, my girlfriend was standing behind me when I read your post, and she yelled a loud "Yes, he is!!" when she saw your comment about me not being able to leave things alone

Sound advice I guess, I will leave it alone with regards to the beep issue, maybe it will fix itself like so many other wonderful XM faults..

The suspension message issue though, is still annoying me, will have to investigate that one. The Hydractive light in the dash works, so I'm wondering is there some kind of issue with the switch.... may have to try the spare switch in the gear lever surround I bought of Brian months ago and have been getting around to fitting since...

Hi all,

What a fascinating series of postings.

Both my displays work with no missing pixels. I never realised that the left hand one was supposed to beep at me, I'm glad to say that mine doesn't. Come to think of it, my old Series 1 used to beep to tell me that the LH indicator was duff (it wasn't) or that one of the rear lights had failed (it hadn't). So when it told me the engine water level was low I muttered "lying b***ard" and ignored it - and it was. There's a moral there, something about shepherds and wolves.

Noz, the thought of taking a piece of random information from the ecu and converting it into activated pixels which make sense frazzles my brain! I would be content if I could find some way to shorten the 4 second? average readout of instantaneous fuel consumption. Reading 99mpg when I'm storming up a hill with a caravan on the back is as annoying as running downhill with no throttle and seeing 16mpg on the display!
Regards

Derek

Hi Derek

The Last Mk1/First Mk2 Owners handbooks say that the fuel average is taken on a 2 second interval. Did Citroen change this to 4 seconds for the later models?

Regards

John

Hehe another little "to do" job. My display beeps in all the right places. eg door open etc. My problem is I can't read it due to missing pixels. I have more pressing things to do first!

Hi John,

You are, of course, correct. I don't know where I got 4 seconds from.

But, it then gives a readout of the average consumption over the last two seconds so it is never up to date and seldom accurate. I don't know about the diesels but in the V6 this produces some ridiculous readings. I have driven a couple of vehicles (both Chryslers) which give instantaneous readings at about 1 second intervals and find this arrangement much better. However I do find the average fuel consumption and range remaining readouts very useful.

Incidentally, on the left hand display, I have never seen "Stop lamp test - apply brakes to test" on this car.

Dave, you may have more pressing things to do but it's going to niggle at you until you fix it! We all seem to be seekers after perfection.

Regards,

Derek

This post has been edited by DerekW on January 06, 2007 01:55 pm

If it's any consolation Derek, my fuel display is even more useless (I think it's because it was converted from petrol to diesel). Miles remaining works (for a few minutes, certainly), as does average speed, but MPG etc constantly displays 99.9.... really annoying. Another 'to do' job I guess

As for the 'Brake light test' message, I believe this functionality was removed for S2, which may explain why you haven't seen it. I asked the same question when I got mine....