I would like to welcome everyone on the forum. Just created my account as could not find a similar issues when searing the forum.

Just bought a 2014 x251 3.0 diesel , on my way back home - 200 miles trip I got an error with the tire pressure sensors - this happened only on my way back home - never replicated. I was enjoying the car until recently got a transmission error shortly after staring a car on my driveway.

It took me some time to notice that I can drive the car without any issues , until I turn on the wipers - and that's only when driving with low speed - 30-40mph or stationary. Motorway speed doesn't affect the car.
What I have noticed is that every other wipe , wipers are causing my speedometer jump +10mph and go down straight after that causing transmission error to show and car is in limp mode locked to probably 3rd of 4th gear. . This doesn't happen when driving on motorway with higher speed.

I would love to hear some suggestions.
The main car battery was replaced last year auxiliary battery is @5 years old but it looks like it does hold charge.
What I have done so far - I've unbolted the two ground points under the bonnet - cleaned the connections - no change.

 

I do wonder where to start - should I start with replacing the abs sensor ?

 

Just one thought: Please measure your battery voltage and ask your friend to operate the wipers and check if battery voltage drops when wipers move?
Reason for this could be heavy load caused by wiper arms axel bushings grease dryed up. You can also try to test how well axle bushing moves by adding movement for another arm by hand, and feel if you can sense the force on other arm? (note: You can´t make wiping movement from arms by hand, but there are some play on mechanism verify.

Not sure how to dismount wiper arm axles form XJ. The service and mainteance manual (seek X351 sticky section) might have info how to remove them.

 

You need to start by getting the car hooked up to SDD and see what codes it has. Just randomly replacing parts will be very unlikely to work. These are complicated luxury cars.

Do you have an ABS error code? Are you going to replace all 4 of them? See the problem?
You need to troubleshoot the problems first.
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I understand that - the problem is that there is no error code associated with the fault.

What I've done before was to lube the wiper arm to see if that help - no change.
After that I have changed the whole wiper arm with the new wiper motor - unfortunately no change.
It all looks like a ground problem now - but where should I look .. is there any ground points near the transmission ?
​​​​​​​Completely lost. It is lear now that it is not a mechanical fault but electrical.

 

Did you measure the car's voltage as suggested above?

Again has the car been connected to a SDD system?
That is the factory tool and it is needed because there are very likely to be errors but your current scanner can't see them.
What scanner are you currently using?
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Wiper switch could have an issue. The indicator stalk is known to fail sometimes (the headlamp portion causes problems) . The design of the wiper switch is similar.