Speedo problem

Hi, the speedo problem I mentioned here already still exists despite having installed a new speedo transducer recently. When starting to drive it all works fine but sometimes after some 50 kilometers the needle goes irregularly up and down and after some time down to zero where it rests till the end of the drive. Next morning everything is fine again. The phenomenon always leads to a momentary loss in power but with speed control on one can continue to travel at the same speed. Any ideas where to search further ?
Best regards,
Matthias

Sounds electronic, sounds like the problem is that you have post 2007 (TDCi) model.

Yes indeed, it is a 2015 model, but what do you mean with sound electronic?

LRODiscoII said:

Yes indeed, it is a 2015 model, but what do you mean with "sounds electronic" ?

Click to expand...

Sorry, have corrected the typo.

What I mean is that the speedometer is electronic, getting the information from a hall effect sensor in the transfer box which also supplies information to the ECU.
You could have issues with the transducer ring, the sensor or the cable/connections.

My defender has a mechanical speedo, it uses a plastic gear wheel (in the transfer box) to spin a 'square ended' cable that drives the speedometer directly. I don't have an ECU.

I think you would need some sort of diagnostic software to monitor the hall sensors output to see if that was causing the issue.

miktdish said:

Sorry, have corrected the typo.

What I mean is that the speedometer is electronic, getting the information from a hall effect sensor in the transfer box which also supplies information to the ECU.
You could have issues with the transducer ring, the sensor or the cable/connections.

My defender has a mechanical speedo, it uses a plastic gear wheel (in the transfer box) to spin a 'square ended' cable that drives the speedometer directly. I don't have an ECU.

I think you would need some sort of diagnostic software to monitor the hall sensors output to see if that was causing the issue.

Click to expand...

miktdish said:

Sorry, have corrected the typo.

What I mean is that the speedometer is electronic, getting the information from a hall effect sensor in the transfer box which also supplies information to the ECU.
You could have issues with the transducer ring, the sensor or the cable/connections.

My defender has a mechanical speedo, it uses a plastic gear wheel (in the transfer box) to spin a 'square ended' cable that drives the speedometer directly. I don't have an ECU.

I think you would need some sort of diagnostic software to monitor the hall sensors output to see if that was causing the issue.

Click to expand...

Ok , thanks. I will try a diagnostic tool then.

Ok, I checked with a diganostic tool which said :

U0401​

So what now ?

The meaning of fault code U0401 is: Invalid data received - engine control module (ECM)

Doesn't help much does it .... although it inspires me not to get a car with an ECU