hi guys and girls, I have a problem with my speedo on my 98 xj8, the other day the speedo went nuts saying I was doing 150mph, I was doing about 30mph, now the speedo needle point's straight down with the engine running but not moving, it does move as I gain speed but says im doing 0mph at about 40mph. does anyone know what the cause is or/and how I go about fixing this to make the speedo go back to 0mph please.
kind regards
dave

 

can anyone help please??

 

Hi Dave,
You could try the hard reset. Not sure if it will work but worth a try.

Just disconnect the negative lead from the battery and touch it to the positive terminal.

Make sure you have the radio code first.

Hope this helps,

 

If hard reset doesn't work; the speedo is driven from the right rear ABS sensor.
Try cleaning it, and testing for bad connections or broken wires.

 

thanks for the replys, I will give them ago in the next few days. thanks again for your help.

 

On the subject of a "hard reset". Do you touch the negative to the positive terminal while the positive is still attached to the battery? That sounds like a recipe for a fire!

 

If you think about it carefully, nothing will happen other than a small spark from the capacitors discharging.

If you are uncomfortable doing it this way then disconnect both leads and touch them together, either way the result is the same.

Always disconnect the negative first which ever way you do it.

 

You wont get any sparks if that is what you are worried about because the car is no longer attached to the negative terminal, all this does is quickly drain any residual power in the car modules, it is a similar effect to leaving the car for a while without the battery connected at all...... Just a lot quicker and the theory is everything gets reset to factory......

 

thanks for the reply's and suggestions people, I think I have now solved the problem by pulling the fuse f18 in the left heel board, turning the ignition on (this reset the speedo to 0) then putting the fuse back in, I am still to road test it but the signs look good. thank you again for your time. hope you all have a very happy new year.

 

Hopefully that is you sorted Dave.

Have a good New year yourself.

Thanks for the update,

 

I hope its sorted to, I will report back later of any news.

 

Looking forward to see if Dave's fix works (fuse number 18 in rear left hand heelboard fusebox is protecting the instrument cluster).

Happy New Year

Jim Lombardi

 

sorry for the slow reply, it has solved my problem. all working as it should. just to make it clearer the fuse was not blown, I just removed it turned ignition on to position 2 that reset the speedo to 0, turned off ignition, put the same fuse back in and hey presto it worked, I must admit tho it was more luck than judgment. I don't even know where the idea to try that came from, but it worked so I am happy. thank you all again for your help. I really do appreciate it. hope you all have a very happy new year.

 

Glad to hear you have it sorted and now know what speed you are doing.