Hey guys, I'm writing you from Austria! I have following problem with my "new" X358 2.7D.
We got the XJ after the death of my wife's father and the car was unmoved for one year, so the battery was dead and I had to install a new one.

Now from time to time the speedometer is not working and stays at zero, than for example after breaking and short stop at the highway exit sign it works again. Or it works upon start stays at 30km/h and falls down to 0. Than after short stop because of red at an intersection, it works again.
I was in an garage already and the mechanics read out the faults and told me there were some faults and also a fault in the can bus. So they reprogrammed the canbus and updated all modules. After short test drive by the mechanic and again fault readout there were no faults..
2 days later the problem occured again.

Any ideas what it could be? Faulty Abs sensor? Earth problems as described by the X350?

Appriciate any advise
Kind regards from Austria!
CHRISTOPHE

 

I forgot to mention the odometer/mileage is working. At my way home it showed about 20 kmh to much and know after turn off the icognition the meddle stuck at about 20....

 

I'm not sure offhand if the vehicle speed is taken from an ABS sensor or from the transmission VSS. My thought is the transmission sends vehicle speed info to the cluster and ECM. A mechanic with a decent diagnostic tool should be able to view the data stream from the ABS and transmission and see what vehicle speed is being reported, or if there's an error. I would expect several codes to be set if the car loses the VSS. "Reprogramming the CAN bus" sounds bit bogus to me--maybe just what your mechanic told you to put it in general terms. The CAN bus is simply a 2-wire network of modules that speak to each other, it can't be reprogrammed as a whole. Individual modules can be flashed, but typically that is a dealer or Jag specialist only job. You may need a mechanic with more expertise to correctly diagnose.

If the vehicle speed data is not the issue, I would suspect an actual cluster fault. The stepper motors for all the gauges can fail, it happens on many makes and models. You can send the cluster out to be repaired.

 

Thanks for your replay, I was with the car in a dealer/Jag official garage. And after deleting and updating all the modules the mechanic made a test drive again and no more/new codes in the failure log.

Do you think it's possible that if there is a problem with the speedo stepper motor, that it works and than from one second to the other(after standstill) it fails to work after restarting the icognition again?

Cheers Christophe

 

Yes make sure whomever is working on the car uses and understands SDD. This is the factory diagnostic software and is mandatory for what your looking for.
They should be able to pull up the problem using SDD.
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This sounds like a case where actual codes (DTCs) are, as usual, needed, for each module.

 

Yes, I think a stepper motor can fail in exactly this manner. But that assumes the signals are there to your IP cluster and there are no other underlying issues.

Agree with JagV8--if the VSS signal is being lost there will be multiple modules setting codes. The IP can set its own codes for loss of signals received over the CAN bus.

 

Hi all,

I had this very problem with my speedometer. It is usually the stepper motor that causes this problem. The cogs teeth wear down over time and you get this problem. Essentially the cogs slip and the needle cannot be kept at its place. Mine would work after a while and the speedo would slowly drop to zero even when travelling at a steady speed. Sometimes as well, the speedometer needle would sit at zero even when starting the car. The stepper motors can be easily replaced but you have to get the cluster out, which is actually quite easy. Once out you can desolder the stepper motor and solder a new one in it's place. That fixed the problem on my car. The biggest problem I had was sourcing a suitable replacement stepper motor. I would also replace the stepper motors for the other dials in the cluster at the time as you would already have the whole cluster out of the car at this point.

Thanks,

Chris

 

Can you tell is where you sourced a new motor?

 

I'd buy a used cluster and swap a motor out of it.

 

As JagV8 states that is one way of doing it. Just make sure that the old cluster stepper motors are working and not worn as well. I did this fix quite a few years ago now and I can't remember where I got the new motors from. I'll look through my orders and if I manage to find it then I'll let you all know.

Cheers,

Chris