Oleg_850

All,

I have E500 MY05 equipped by the tire pressure control which displays the actual figures on the dashboard and just faced with the problem: I checked the pressure in all tyres with the air-gauge in-build in the tire compressor, checked it again by the separate air-gauge - everything was all right. While re-activating the pressure control system I noticed that the pressure in the front right tire in slightly higher than in the left right (about 2-3 Psi). I decided to activate the system, pressed "R"-button and began to drive. After 15-20 min of driving I've got a red mesage on the seedo said that F.R. tyre was low, however the displayed figures said that the F.L. and F.R. tyres now had the same pressure.

Looks like the F.R. tyre got low. I checked the pressure by the independent air-gauge - everithing was fine. This persisted several times.

Does anybody faced with the same mystic issue?

Thank you

Diesel Benz

You only mention relative figures, what is the absolute pressure on your tyres? The system would give a warning even if all tyres had the same pressure if the absolute pressure was too low. This fixed limit may appear a bit differently for each sensor.

I assume you had sufficient pressure and the issue is something else but you could confirm this first.

Oleg_850

I did 2,3 atm for front and 2,7 atm - for rear

Diesel Benz

That should be sufficient to avoid the fixed low threshold.

Oleg_850

Nevertheless, the problem exists - will deliver the car to the dealership - hope that this is just a failure in data exchange and can be fixed at low cost

MB211

Could be as simple as a bad sensor (low life) in that tire. The sensor may be interm dropping the signal to the control unit causing a false reading.

konigstiger

When a sensor problem is suspected remount wheel to different location, erase DTC and see if problem moves.

Oleg_850

Today experienced the same issue as in the past. While started the display showed 2,3 atm for F.L. and 2.5 for F.R. After 10-15 driving got a red desplay said the F.R. has inssuffecient pressure, while the display showed 2,3 atm for both fornt tyres.

Approached the office and let the car stay for 4-5 hours. Start the engine - displayed 2.3 for F.L. and 2.5 for F.R. Decided to blow off F.R. - while separate air-gauge showed 0,2 atm in-build showed 2,5 atm. Had the F.R. tyre blown up to 3 atm by separate air-gauge - in-built displayed 2,5

I could understand if this would caused by a sensor problem and the system displayed the it is inoperative (like when I use the wintertyres mounted to the wheels without sensors), but now it looks like the system works, but the sensor transfers the wrong data.

I do not have a clue how the sensor works - maybe it can be somehow cleaned?

Thanks

Diesel Benz

The tyre sensors are inside the tyre, there is no need to clean them and it would not be possible either (without removing the tyre).

But why did you not swap the front tyres as suggested? Since the issue is not always present, it would be difficult for a workshop to diagnose. But if you can tell the issue following the wheel from the right side to the left, then it is obvious where the error is.

Oleg_850

I will try, but as mentioned I need DТС to erase - what is ment under this abbriviation? just to have the system reactiveted by pressing of R-button?

konigstiger

Note sensor battery is not replaceable. To clear DTC (diagnostic trouble code) reactivate the system – trip odometer reset button while viewing current inflation pressures for each tire in display.

Oleg_850

Thank you, Dan. I will inform on the progress