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How to reset tyre pressure warning?

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52K views 9 replies 7 participants last post by  AlfaCrisis  
#1 ·
Had a 1000 km fast motorway drive and got a warning that one of the front tyres was low, which after checking was not the case (left was highlighted in yellow with exactly the same pressure as the right one) and later got another warning, this time from the rear where pressure was dropping from 2.3 bar to 1.6 bar when I pulled up. This one turned out to be a nail in the tyre, which was repaired.

Now, going over the tyres again and increasing pressures, the tears have registered while the fronts are still at 2.3 bar, even if they were inflated to 2.6 bar.

Is there any way to reset the warning system, as per other manufacturers, when stationary or is it a question of driving some distance for the system to autoreset? Or does it warrant a dealer trip, which would be very silly?
 
#2 ·
I found the sensors are not very accurate beyond 2 psi. Let me convert that to bars and post back. I would say just boost them up a bit more, shut the car off and on a couple times or even drive around. The computer checks are timed and sequenced so it may take a bit to clear it out. Or you can use an OBD2 reader to clear it.
 
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#3 ·
Bars comes back as 0.1378952 per 2 psi. 0.3 bar should have been enough.
 
#7 ·
I have found my car to be even more picky. My door jamb says 35PSI front, 37PSI rear, but I have to put 37PSI front then drive for 20-30 minutes to get the fault to clear.

I have no idea if European spec cars behave the same.

I suspect that the TPMS increments are 0.1 BAR (1.45 PSI). BAR (==atm?) isn't really a metric measure either though, shouldn't it be Pascals = Newtons/m2 or kPa or some such?
 
#5 ·
Yes, I've found the TPMS to be inaccurate, too, and also wonky, for that matter. What I had success doing was overinflating, to get rid of low pressure indication, then backing down to desired pressure. Indicated pressure still wasn't reading correctly, but I used an external gauge to put it where I wanted, so I was comfy with that, and after some time TPMS came around and evened out, if without matching external gauge readings.
 
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#9 ·
So just to report back on the outcome: driving a few kilometres the TPS warnings slowly went out (rear first and then the front), so no way to calibrate it when stationary.
 
#10 ·
As best we can tell:

1) There is no “calibration” possible. The programmed pressures should be adjustable via an Alfa service computer, but that hasn’t been confirmed. There is also the question of if a dealer would willing reprogram.

2) The Giulia will correctly detect the location and pressure of tires, even after rotation, but can take up to 20 minutes of driving to do so. The fact that alerts are set based upon the position and pressure combination argues the settings are programmed into the system.

3) The alert threshold is right about 25% low.

4) After an alert, a reset will not occur until the tire is aired up to at least the set pressure, and then driven.