Speedo stops working when warm!!

[Iwannabongo]

Hi all,
I am need of your help.
My speedometer works when started up and all is good, but when I turn the ignition off and on again while warm the speedo stays at 0. When this happens the gearbox then will not change through the higher gears. Also the hold button will not work at this point and nothing when changing shift to S or L.
This carries on doing this until it seems the engine is cold again.
I have checked the ATF and it all looks OK. I have taken the speedo off to check for wiring, as some people have suggested on here, but all is OK.
Any help is much appreciated.

[Simon Jones]

Does the odometer stop working as well? Have you got a speedo chip fitted or has the dial been replaced to show MPH? Its not unheard of for these conversion chips to fail which could then short out the signal at the gearbox which could then tell the gearbox management that the vehicle is stationary. Remove the instrument panel and see if you can find a small box with 4 wires floating around, then disconnect the feed that goes to the gearbox (blue wire with a white stripe I think). If it then runs fine, you know it is the chip or the speedo unit at fault.

This was one that was fitted to by previous Bongo. The yellow wire was the input and the blue was the output to the back of the speedo.

[Iwannabongo]

Thanks for reply Simon.
I see you are from my home town Nice place, shame about the traffic
Yes the odometer stops working. I have got plasma dials in mph fitted, so I presume there is no chip.
I am hoping it isn't the gearbox at fault, as it could be costly to sort out!

[Simon Jones]

There are 2 types of plasma dials: 110 or 180 MPH (tad optimistic ). Which one do you have?

http://www.visual-performance.co.uk/com ... 708760.jpg

http://www.visual-performance.co.uk/com ... 708861.jpg

[Iwannabongo]

Ah, I never knew they had 2 different types.
Mine is the 110mph, as shown in your first pic.
Does this mean it has a chip in the back???

[Simon Jones]

Yes, I think so. If you get stuck, drop me a message and we could meet up at some point. It's only a 5 minute job to remove the instrument panel to take a look at what's behind.

[Iwannabongo]

Thanks for the offer of looking at it Simon.
I will take the speedo off on Monday as I am away at the mo and see if this chip is there.
I will keep you updated with my findings,
thanks again

[Iwannabongo]

I took the Speedo off today and there doesn't seem to be any chip behind.
I unplugged all the connections behind the speedo and took it for a drive, but the problem still exists.
It looks like I am going to have to look elsewhere

[g8dhe]

If you drove it with the Dashboard disconnected then yes the fault will have remained its the Dashboard that supplies the pulses to the ECU;

The connections from the the drive shaft speed sensor are on the C1-03 connector into the unit within the dashboard on 1A and 1B then the dashboard module processes them and provides an output to all the devices that need to know that the vehicle is actually moving, that signal comes out to the PCM or ECU on 1D connector.