EFR

This is the first car I have had with "advanced" TPMS, meaning the supposed actual tire pressure is displayed on the screen vs just a warning of low tire pressure. My tire's, via two seperate gauges, all show 36 lbs, which is what is called for on the door panel. The display screen on the car info screen shows all at 32 lbs. This is when tires are cold, and has been checked three times over three days. While in theory, having such exact pressure readouts available on the dash is great, if I believe the dash, they seem fairly low and need filing. If I believe the two different kinds of external gauges I use, they are fine. Has anyone else verified/compared the cars readout vs your own pressure gauges?

MI-RDX

My dash pressure is the same as the readings I get on 3 different gauges.

Dizzyg12

romer

My 2019 Advance door jam shows recommended cold tire pressure as 33 psi all around, not 36. That said, I've checked my tire pressure with different gauges and things are running pretty true on my dash read out.

EFR

OK, maybe it's an A-Spec-non A-Spec thing, but mine definitely says 36 on the door. I have a digital and analog gauge that both say 36 but the dash shows 32 all the way around....hmmmm.

Madd Dog

Dizzyg12

PRM-RDX-3G

I find the air pressure sensors are very sensitive to temperature. Mine were at 36lb. It went down to -10C in Toronto last week and they read 29lb setting off an alert. Once 20C the tire sensor readings and independent gauge settings are pretty close

MI-RDX

It's not that the sensors are affected by temperature but the actual air pressure changes. Simply said heat causes air to expand increasing pressure, and cold causes it to contract reducing pressure. A rough rule of thumb is tire pressure will change by 1 PSI for every 10F change in temperature. Filling to 36 PSI at 70F and not adjusting seasonally will result in 30 PSI when temps get down to 10F.

zroger73

It's less likely that all four TPMS sensors are reading 4 PSI low. It's more likely that your pressure gauges are reading 4 PSI high. Here's some information I posted on another forum last year about this subject.

https://www.ridgelineownersclub.com/...ml#post2742921

gtssenior

I still do a weekly check with my "stick" gauge when the tires have been at rest for awhile since over the years that has worked for me and maybe you can't teach an old dog new tricks. The dashboard readout seems to add a psi or two to that measurement and the Acuralink maybe another psi. I don't think the small differences contribute to any road performance, improper tire wear, or safety concerns. To me the digital readouts plus the low tire pressure icon do add other sets of "eyes" especially when you take a nail and develop a slow leak between my "stick" gauge checks.

losiglow

iTrader: (1)

The aftermarket sensors on my OZ wheels consistently read about 3lbs. higher than a tire pressure gauge. Stock wheels with winter tires are right on with the gauge. That's on a 4G TL though.

Shampoch

RDX-Rick

My experience with AcuraLink on my 2016 RDX, is that the app shows the status of the vehicle when it was last turned off. For example if the door was open when you shut off the engine, then you got out and shut the door, AcuraLink will show the door opened. More info on this "Feature" is described in this previous GEN2 post.. LINK

The reason I bring this up, is that when you last turn off your RDX, it is probably when you returned home from a drive. The tire pressures will always be higher after a drive (compared to after sitting all night), and therefore AcuraLink will normally show higher pressures than what the gauge says first thing in the morning.

Another theory that I have, is that in order to increase the battery life of the sensors, they only send updated data to the car's computer, at 2-3 minute intervals. To set my tire pressure, I measure them with a gauge first thing in the morning, then I drive the car out of the garage, and I usually see the dashboard pressure update in the first 20 meters or so.

Unfortunately these theories do not explain why the OP's dashboard is "lower" than the actual pressures.

I know that tire pressure should only be set when the tires have sat overnight, but as a diagnostic test for the OP, try going for a drive around a few blocks,to give the sensors a chance to update the RDX's computer. Only then, measure your pressures with a gauge and see if they agree with the dashboard display. If they agree using this procedure, then you know there is not a mechanical problem, you just need to set your tire pressures using a gauge, and then trust your TPMS to be accurate, while in motion, after that.

Madd Dog

RDX-Rick

Clicking update on the App, is just telling the App to get a new reading from the RDX's on-board computer. What I am saying is that the on-board computer will not update after the engine is turned off. Everything that was present when the engine was shut off will be sent to the App no matter how many times you press the update status button.

Madd Dog

mrgold35

I've always had an issue with hand gauge -vs- TPMS because of altitude of +5400 feet in ABQ, NM. I'm usually 2-3 PSI higher on a hand gauge compared to TPMS. The pressure difference get greater as I go up in altitude. I sometimes set my PSI to 36 when I hit the ski resorts at +9000 feet with temps in the teens to keep the TPMS alarm from going off if it was set at the PSI at the door levels.

Wander

If you think you're short of air in your car, try hiking the La Luz trail or riding a bike up to Sandia Crest ( 10,650 feet ).
The really sick thing is there are people who trail run up La Luz ( 3775 feet of elevation gain in about 7.5 miles, with sustained gradients of 12%. And it's rocky. ).

Back to tire pressure, I find the TPMS readings consistent with my hand-held digital gauges.

Stick gauges tend to, well, stick.

And hand-held dial gauges are junk once they get dropped, bumped, or looked at a little funny. Not worth the trouble.

anoop

Probably a 20" vs 18" thing.

EFR

Wander

Or 20" vs 19". My winter tires are 18" but all 2019 RDX's except A-spec come with 19" all-season tires stock, including my Advance.

But yes, lower profile tires generally have less total air volume and therefore require higher pressures to support the same weight.

It's possible that the TPMS system is reading incorrectly on OP's A-spec RDX, perhaps because it's not updating appropriately. Dunno. I couldn't find anything in the Owner's Manual about adjusting an offset for the pressures, and the
"warning" threshold would have to be different for A-spec than the other trims because of the higher recommended pressure. I wonder if this accounts for some of the complaints about harsh ride on the A-spec.

Anyone else with an A-spec who can add to the database?

anoop

Thanks for the correction. Not sure what I was thinking when I wrote 18".

Buit15

Trust the door specifications so long as you have the OEM tires supplied with the RDX. If the TPMS reading is 32 and you are reading 36 on multiple gauges, definitely take the vehicle in and ask for a check of TPMS system. Gauges do not lie, but TPMS can and does malfunction.

zroger73

Go buy one of these $395 digital tire pressure gauges with the optional NIST-traceable Certificate of Calibration for an additional $130 then compare it to the TPMS and readings and report your findings.

Buxton Engineering, Inc. - Digital Tire Pressure Gauge

I bet you'll be surprised by the results.

mechonit

MI-RDX

Probably not - no way for the app to directly access the sensors since all it has is an indirect link to the vehicle (I suspect through a Honda/Acura server somewhere). It just asks the car for the information and displays whatever is returned. It's not a particularly smart bit of code.

Peanut67

I'm in Colorado and my dash always shows 2 PSI lower than my gauges. (including a professional gauge). My Chevy TPMS reads the same.

philj

I am in Arizona at 3500 elevation and my dash also shows 3 less than other gauges at morning readings while in garage.