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Got a low pressure light this morning on first start up of the day - i.e., cold tires. Ambient temp was about 60F. System indicated left rear was the culprit at 29 psi. All others were at 31 psi which is 4 psi below spec (35 psi) for my vehicle per door jamb sticker. After 15 minutes of city driving, LR was at 30 psi but warning indicator was still on. Stopped and adjusted pressure in all tires (checked with my digital gauge) and warning indicator turned off as I expected it would.

Based on this, can I rightfully assume that for my tires and vehicle, the threshold at which I'm supposed to get a warning indication is 30 psi? Is there a spec for this somewhere? The owner manual doesn't document a value AFAIK.
 

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30 sounds a bit close to recommended pressure to be the low threshold but I Im not sure as I've never checked the Giulia specifically ...26 is what I am used to seeing in passenger cars ... The values are stored in the RF hub and both the low and high pressure thresholds are normally able to be set with a scan tool. ..I may hook my car up just to see what the values are.....Ill post back if I do..:)
 

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OK, from my Owners Manual:

Operating Example
For example, your vehicle may have a recommended cold (parked for more than three hours) placard pressure of 33 psi (227 kPa). If the ambient temperature is 68°F (20°C), and the measured tire pressure is 28 psi
(193 kPa), a temperature drop to 20°F (-7°C) will decrease the tire pressure to approximately 24 psi (165 kPa). This tire pressure is low enough to turn on the “Tire Pressure Monitoring Warning Light.” Driving the vehicle may cause the tire pressure to rise to approximately 28 psi (193 kPa), but the “Tire Pressure Monitoring Telltale Light” will still be on. In this situation, the “Tire Pressure Monitoring Warning Light” will turn off only after the tires are inflated to the vehicle’s recommended cold placard pressure value.


What this shows is the TPMS will not terminate a warning until you air a tire up to the recommended pressure. I’ve generally found the TPMS warning threshold to be about 12-15% low, so for a 35lb recommended tire, the light should be at about 29-30lbs.
 

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2018 Giulia Ti Sport Q2, Vesuvio/Red, Perf Pkg, CF all over.
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I had warning light come on and found 3 of four tire at 30 and one at 29 in the Infotainment display. Odd thing was the tire showing amber warning was a front one at 30psi. My setup lists fronts at 35 and rears at 33. So warning about front is now understandable. System is pretty exact so good job A.R.
 

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2018 Q4 with Fiamenghi Ti exhaust, Race Mod, and Tecnico wheels.
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I can confirm that for my Q4 with recommended 35f/37r the TPMS warning light comes on at 30PSI and only goes off when the pressure is raised above 37 (front or rear).

MES says that there are 8 (I think) TPMS logic schemes to select and that my car uses scheme 0. Might anyone know the properties of any of the other schemes?
 

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2018 Q4 White/Black, Performance Pkg., Leather Pkg., 35W Xenon, Static Assist, Sunroof, Navigation
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I can confirm that for my Q4 with recommended 35f/37r the TPMS warning light comes on at 30PSI and only goes off when the pressure is raised above 37 (front or rear).

MES says that there are 8 (I think) TPMS logic schemes to select and that my car uses scheme 0. Might anyone know the properties of any of the other schemes?
I can confirm that for my Q4 with recommended 35f/37r the TPMS warning light comes on at 30PSI and only goes off when the pressure is raised above 37 (front or rear).

MES says that there are 8 (I think) TPMS logic schemes to select and that my car uses scheme 0. Might anyone know the properties of any of the other schemes?
LOCKEM... Did you ever find out properties for the other schemes?
 

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2018 Q4 with Fiamenghi Ti exhaust, Race Mod, and Tecnico wheels.
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LOCKEM... Did you ever find out properties for the other schemes?
Nope, too busy with other things and nobody volunteered to do it.
 

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2018 Q4 White/Black, Performance Pkg., Leather Pkg., 35W Xenon, Static Assist, Sunroof, Navigation
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haven't actually tried it, but seems you can just set the nominal pressure(s)
on a side note, my displayed values are spot-on......
see:
Thank you for the screenshot.
Lowering the nominal pressure scheme to 29 PSI will solve my issue.
My display pressures are also right on the money.

Thanks again!
 
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