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I believe I'm having issues with the tire pressure monitor displaying the correct tire pressure, albeit only by a few PSI.

I've measure all 4 tires with two different tire pressure measurement tools and both display the same exact pressure for all 4, but inside of the vehicle, I get different readings for all 4 tires.

Does anyone have any experience with calibrating the tire pressure display? Or is this something I should take in to get looked at?

Thanks!
 

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A video on how to set the TPMS is about 3/4 a page down here: https://www.mbusa.com/mercedes/owners/videos/year-2015/class-GLA_Class/model-All

As far as the calibration, I experienced the same phenomenon as you - the displayed pressure did not correspond to the measured pressure. I surmised the system just wasn't that accurate. I know of no way to get the system reading to agree with the measured reading. Since it's use is as a relative measurement, I didn't worry all that much about it.
 

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Mine read about 2psi less than actually measured. I agree that a relative measurement is all that's needed. A drop by more than about 4-5 psi will trigger a warning light. And it's easy to set the TPMS to a custom setting.
 

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Your variances doesn't surprise me.

I'm assuming your external tire pressure gauges are over the counter versions purchased at an auto parts counter. What do you think the accuracy of those inexpensive gauges is? Look at it this way, a $300 engineering lab pressure transducer is rarely capable of more than +/- 0.5% accuracy. Relatively speaking, even a digital tire pressure gauge costs about $30. I can't find any accuracy stated for a tire pressure gauge, but again relatively, would expect it to be in the +/- 5% range (one order of magnitude same as cost difference).

That being said, +/- 5% of a 60 PSI max scale is +/- 3 PSI, or total of 6.
 

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Mine read about 2psi less than actually measured. I agree that a relative measurement is all that's needed. A drop by more than about 4-5 psi will trigger a warning light. And it's easy to set the TPMS to a custom setting.
That would make sense since as you can imagine with the temperature changes our vehicle goes though on a daily basis they need some slight range to accommodate for that which i'm guessing 2psi range does.
 

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I have the same problem though the displayed pressures are exactly the same for the fronts as for the backs.

Fronts
I pressured @ 2.3 bar (TPMS displays 2.4),

Backs 2.0 bar (TPMS displays 2.05).

I read in the manual it says that tyres should be filled at cold between specific temps (which I did) . It also mentions that the system is calibrated 'at sea level'. Also temperature fluctuations will affect the TPMS.

The dealer told me the levels were an acceptable tolerance, however I would prefer to set the calibration somehow to my own readings !
 
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