Message run flat indicator inoperative on my 2012 Slk 250

As you may be aware of, Mercedes does not approve of "unauthorized" repairs. Having said that, most of therse systems function as follows:
1) 4 wheel sensors ( with internal "batteries" ) send signals to an on-board pick up that relays the signals to the dashboard indicator light.
2) If they all ceased operation at once, I would think either the on-board sensing mechanism has failed, or the computer has "lost the signal".
In any regard, likely Mercedes will be the place to fix this.
God bless your efforts.

Perhaps the batteries in the key fob are flat or low?
Good Luck :)

All that at once sounds like a bad ground. Check battery to engine, battery to body and engine to body grounds.

Check the pressure in your tires. If it's good then the sensor system has failed.

For speedometer problem click the link below :---

How to trouble shoot speedometer?
http://schematicsdiagram.blogspot.com/2011/06/speedometer-not-working.html
-----------speedometer not working? http://technoanswers.blogspot.com/2012/01/1996-fiat-bravo-speedometer-not-working.html
---------Speedometer runs backward?

http://technoanswers.blogspot.com/2012/01/speedometer-runs-backward.html

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Warning lights on and speedometer died? http://howtobyme.blogspot.com/2011/08/warning-lights-on-and-speedometer-died.html
---------ABS & Brake lights warning indicator steady on dash and speedometer not working? http://howtobyme.blogspot.com/2011/11/abs-brake-lights-warning-indicator.html
--------Odometer works properly but speedometer works intermittently? http://technoanswers.blogspot.com/2012/01/odometer-works-properly-but-speedometer.html
----------speedometer is jumping? http://schematicsdiagram.blogspot.com/2012/01/isuzu-rodeo-speedometer-is-jumping.html
-----------This will help.Thanks.

#PIT4878: Service Park Assist Message / LEDs Stay On Or Inop - keywords B0968 inoperative lamp led light lit module reverse urpa - (Jun 12, 2009) Subject: Service Park Assist Message/ LED's Stay On or Inop Models: 2007-2009 Chevrolet Silverado 2007-2009 GMC Sierra With RPO UD7

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern: Some customers my comment of a Service Park Assist Message on the DIC and/or the LED indicators at the right rear pillar staying on or inoperative. This concern could be caused by the wiring harness to the LED indicators being pinched under a ground eyelet at the right rear pillar, as shown below.


other issues could be the problem such as poor connections at each sensor or damaged sensors. to clear URPA codes,place ignition in run,(engine OFF),shift into reverse and turn key OFF.place shift lever into park and retest operation of URPA. if still inop URPA code(s) need to be retrieved before further diagnosis can be accurately done.

Usually it's the opposite. The speedometer works and the odomater and trip meter go inop. Most likely the speedometer assembly is bad. If the odometer is working you have a signal from the gray and black wire .

Yes your speedometer, and odometer are controlled by your speed sensor.

You should have a speedometer cable that runs from the back of the trani, thru the fire-wall, and into the back oh the gauge cluster.

It may be a faulty speedometer with a short inside, or a short on speedometer wirings or connector.

Whenever car vibration cause the wiring to short, there you lose speedometer and trans functionality.

You need to access the speedometer connector and wirings to
instrument panel to fix this.