2004 Berlingo Speedometer not working

[xeasi]

Have a problem with my 2004 1.4i 55kW Berlingo. It's a 5spd manual. The speedometer doesn't work and as a result the odometer wont increase either. Everything else functions good.
So far I have replaced Front-Left ABS/Speed sensor. Also I have changed the speed sensor on the gearbox. Neither changed anything. Have also tried a different instrument cluster which didn't help either.
I used AutoCom and it gave me an Instrument Cluster error. Don't remember the exact fault code but the description was "Faulty speed data" or something like that. Another interesting thing to point out, is that AutoCom could not establish communications with the Brake/ABS module. However I have no warning lights on the dash about it. How possible is it, that the instrument cluster is not able to receive the ABS speed sensor data due to a faulty ABS module? And where would the ABS module be located?

[oilyrag]

I'd hazard a guess that the speedo only picks up the signal from the sensor on the gearbox/diff housing and does not interact with the ABS.
Also some readers simply do not communicate with ABS/Airbag systems at all so no readings are generated, or if you have no faults with yours could it be that they are not there to be seen. Worth taking a really close look at the plug/wiring from the gearbox sensor as there may may possibly be a break in the wiring.

[cancunia]

Hopefully @saskak will see this and be able to confirm, but IIRC the instrument cluster is driven by the Vanbus / Canbus network rather than individual signals. If so, the speedo signal will go to ECU and be encoded.
I don't have time today, but can probably find the wiring diagram over the next few days if needed.

[saskak]

Hopefully @saskak will see this and be able to confirm, but IIRC the instrument cluster is driven by the Vanbus / Canbus network rather than individual signals. If so, the speedo signal will go to ECU and be encoded.
I don't have time today, but can probably find the wiring diagram over the next few days if needed.

I think it is CAN bus (might be wrong though) and the speedo signal needs the interaction with the ECU in order to drive the speedo, i.e. the signal does come from the sensor itself. The OP has already tried a different cluster, so it is unlikely to be the cluster itself. I am not too familiar with the CAN bus itself, so difficult to advise anything.
It is rather interesting how only the speedo does not work and the odometer as well, so no speed data at all comes through.

[xeasi]

Will have a look at the speed sensor wiring plug and perhaps try to clean it. Any way to test the plug with a multimeter perhaps?

[Gryffindor]

I believe it produces a regular pulse, whose speed changes with road speed. Might not show up well with a multimeter. I think canunia suggested a 12v LED in another thread very recently? LEDs can flash at very fast speeds, with a clean on/off unlike trad light bulbs.

[oilyrag]

The plug lives in a mucky area and likely to be covered in crud.  The pins are very delicate so be careful not to fold one over when removing/refitting. 
I had a cracked feed wire on mine and once cleaned, soldered & sleeved, it fixed it. You should be able to pick up the feed, (possibly 12v, but could be lower?), and earth. Then assume that the remaining wire is the signal one!
I believe the 'raw' signal generated by the sender does go off into the brains somewhere to come out again as another signal to drive the speedo .