Ongoing saga - adding 3-line MFD and CC with Diagbox

[Rasputin]

Okay, since I last reported not a lot has happened to my car because of work, but surfing the web has taken the research a lot further.

It now seems better to bring my separate threads back into one, which will make updating this saga simpler as it progresses (hopefully). But it will have to cover a number of mini-themes!

Given all the advice & help I've been given here and found online, the immediate conclusion so far is that adding CC as well as a 3-line MFD should be straightforward:

• Despite earlier concerns, it seems I can just swap the end cap of my wiper stalk
  
• My current com2000 will probably work and not need replacing
  
• My com2000 has a socket for a CC stalk
  
• An LCD version of the instrument cluster is in the pipeline (ta to those concerned)
  
• On examination, my car already seems to have both pedal switches needed for CC
  (but why has it already got a clutch switch??)
  

So the plan of action I had decided on, whilst waiting for the cluster and a wiper stalk cap, was to install the MFD and temp sensor, find Diagbox, and test the trip functions by using a multimeter probe to short the tracks in the wiper stalk (see earlier threads).

If all goes okay, then I could later add the cluster and CC stalk and try to get that up and running as stage 2.


Then I got a bit distracted by a Youtube vid, wondering whether it would be possible to add a 'Peugeot type C' display instead of a 3-line 'EMF-B' MFD:

https://www.youtube.com/watch?v=WAU_yHYznWs

One intriguing point is that apart from the display's height, it looks otherwise quite similar to our MFDs - same width, screw fitting, etc.

Another is that once the guy has it installed, he then 'programs' it using the buttons on a standard PSA radio. It is a CD one whereas mine has a tape slot, but the other controls look similar. So, knowing from earlier threads here that the MFD and radio are linked anyway, would a type C display work in a Berlingo?

A third is that this seems to suggest that rather than the MFD controlling the radio, this 'control' function is not one-way. More on that in a bit...


The short answer appears to be no - they have different connectors with only 12 pins (see about 0:45 in the above video) whilst ours have 18. But then on looking into what connections are actually made, including finding cancunia's quest to find out whether the external temp sensor can use 2 of our units' 18 pins, I learnt that of the 18 pins only 5 are apparently used! So this might - just might - also be the case with the type C display, and so it may be possible to install one after all. But I'll leave that for others to try.

Details of the 5 pins are given here (* but see the end of this post as well ):

This looks very much like CANBUS then (elsewhere I found out that the yellow line is permanent +12V and the red is bus +12v).

But the thread this comes from - see post 105 (I can't find out how to directly link to it):
https://www.eevblog.com/forum/projects/v...2002)/100/
makes it clear that this is not CANBUS (controller area network) but VANBUS (vehicle area network).

New to me, so yet another distraction ensued... in short, PSA cars have a second internal bus network which is dedicated to what I'd call the human interface, including radio, dash displays, airbag ECU, and - crucially for me - steering wheel stalks, com2000s, and cruise control.

A few VANBUS links I found (very sparse):

• the above Peugeot thread in full
  
• http://jimbutterworth.co.uk/5bus.htm
  
• https://www.eevblog.com/forum/projects/v...2002)/100/
  
• https://en.wikipedia.org/wiki/Vehicle_Area_Network
  and its links to ISO specs and this site:
• http://graham.auld.me.uk/projects/vanbus/index.html
  

I even read in one post somewhere - can't find it now - that the MFD (any type) contains the brains of the VANBUS network - so those who have in earlier threads in this forum suggested that the MFD contains the trip meter processor because its chips are far too exotic just for a clock, it seems that you are right, but it also goes a lot deeper than that!

All very interesting, several more hours killed, and still no sign of my Diagbox - but in noting that the VANBUS network includes com2000s, I then looked into this with my CC hopes in mind.

Turns out that I was very fortunate that my earlier trick of shoving a screwdriver down the wiper stalk didn't work because its shank wasn't long enough to reach anything in the com2000, because they are not in the slightest means empty boxes to hold the stalks in place, as I had wondered. Just look at this internal view of one:


https://citroenc3owners.com/tips-for-any...-t467.html

It looks like my desktop PC! Certainly on a par with games consoles.

More looks inside different coms:
https://www.youtube.com/watch?v=0TkwJcouXZk (English, very rough treatment!)
https://www.youtube.com/watch?v=WQl7tGHgnJs (French but so much more refined!)
https://www.qdi-ltd.co.uk/peugeot307indicatorstalk.html
and especially this one for its multiple good photos:
https://www.ajcreatif.com/car_peugeot_20...stalk.html

It is disconcerting to see how similar they are not to each other after all!


Furthermore, as part of this I also made a bit of progress on my earlier query why com2000s have so many multiway connectors when only the four standard bus pins might seem enough.

First, the three cables ending in plugs which hang out of the front of com2000s. As some have said, one is for the steering wheel airbag. One is for the horn, natch. But the third one is apparently for CC controls when they are mounted on the steering wheel - so why does it seem all com2000s have 3 such cables? What does no.3 do in ordinary steering wheel setups?

Going further, I found it reported that there are some some test ports on the back of com2000s; it wasn't made clear which ones they are, but I think they are the two smaller ones at the bottom outer corners on the backs of the units - see the photos in my other post (https://www.berlingoforum.com/thread-20025.html) and also the photo below.

This site advertises a test lead which seems to use these two ports:
https://www.auto-chips.com/peugeot-psa-j...p2224.html

It would certainly be easier for an engineer to access these two corner sockets of a com2000 in situ than any of its other sockets.

The next discovery regarding one of the other larger sockets got me worried. Referring to a different com unit (96576794XT) in his website, Jim Butterworth states that the blue socket is for cruise control (http://jimbutterworth.co.uk/5cruise.htm). What I think he means is that this is the com2000's VANBUS connector.

(Fascinating site overall, BTW.)

Here's his photo of the back of that com unit:

   

As you can see, the blue socket is in between the other two, roughly the same position as the missing/taped over socket in my com2000! So can I install CC with my com2000 or will I have to replace it after all; and if so, which one with?

So now, instead of not worrying too much which com unit it gets swapped with, to not needing to swap it at all, now we have a nightmare!

Even 'blue socket' may not necessarily mean 'CC connections ' - not checked yet but I suspect many com2000s capable of having CC don't have blue sockets... and logic suggests they must all have a VANBUS socket... we'll see.


So now I think I will gradually make a spreadsheet of all com units after all. It will I think be based primarily on saskak's info because it is the most comprehensive in terms of variants and may include them all - over 400 - however it does not give part numbers ending in XT etc so will need to be cross-referenced. So for that end I will also make a secondary listing myself from various online sources, with the aim of merging it with saskak's list and including things like car models, stalk functions, sockets, etc. for each unit.

Another idea I might try is to ask my current fave Youtube pirate, BigCliveDotCom, if he would 'do a teardown' of a com2000 if I send him one:

https://www.youtube.com/watch?v=IK06vAlQpOs&t=549s

As was shown earlier, other teardowns are already on Youtube, but they all concentrate on fixing/replacing stalks and ignore the complex electronics. Big Clive would relish doing the opposite I suspect.

But right now I must continue my hunt for the Diagbox I bought last year... no more distractions!!!


* Ah, nearly forgot - MFD pins. I thought I'd have a look at the inside of the one I have waiting to be installed. Unless the pcb has more track layers hidden below the surface one (likely) which have tracks leading from the 18-way port's pins (I suspect not), then at first sight it does indeed appear that only 5 of the pins are used, but different ones:

Above diagram
Pins 7, 9: +12V
Pin 8: gnd
Pins 4, 18: data

My MFD:
Pins 1, 3: both thick tracks, probably +12 V
Pin 18: medium width track - gnd? Not obviously linked to the pcb's general ground plane though
Pins 6, 8: each lead to groups of resistors and caps near ICs - data?
Pins 9, 10: each leads to one capacitor and then a plated-though hole, presumably making electrical contact with an inner track layer in the pcb. Function? No idea.

I would have expected one thick track for gnd and two medium ones for 12V.


Lastly, Jim Butterworth managed to improve his MFD by replacing the 3 bulbs with 24 LEDs, and his written description of the board containing the 3 lamps and how to access/remove it tallies with the dismantling of my 3-line unit:

http://jimbutterworth.co.uk/5display.htm