Why does my tire pressure read low

My truck always read low tire pressure. I understand it should be like 34 but with cold weather is gets lower. Main question is my left tires both read 29 in yellow (reason for the alert being on). My rights read 28 and 30 without the yellow. Why does the 28 not have the yellow around it. Makes no sense to me.

 

What does a manual gauge say?

 

Is 28 the top of the range for the front and 30 the bottom for the rear? Sounds unlikely but I can't say I remember what the manual says specifically. Or maybe there is a problem with those sensors and that is why they are yellow?

 

I have sensors, what the hell is this ‘manual gauge’ you speak of?

Spoiler

could be batteries going bad

Spoiler

I’m glad my truck won’t have those things

 

Why would you specifically not want them?

 

His left front reads 29 and is yellow. His right front reads 28 but isn't yellow. That's what OP is referring to

 

Yeah, I was saying that 28 could be the max for the front and 29 is too high. I know this isn't correct for the vehicle, just spitballing how it could give a yellow warning for those numbers. Low battery or something is what I'm putting my $ on.

 

I see what you mean now. Although they said 34 is what the normal cold reading should be. Regardless, OP needs some more air.

 

For the exact reason OP is making this thread.
I’ve never liked the idea of the TPMS. The older rotational based systems are fine, but having to deal with sensors and just additional hassles when working with the rim/rubber/programming, then that stupid light in the dash if you want to not have sensors for another set of wheels, all the possible issues and expense trying to fix that issue, just fuck off already.
Seeing no TPMS for my spec made me incredibly happy.

 

I'm sure he's talking about a hand held tire pressure gauge.
Like the ones we used before tpms.

 

Yes, thank you for walking me through that, Andrew.

 

You can just disable it if it's broken or spare wheels but until then you get useful info that can make you safer.

 

Pass. Don’t have them on my bikes, don’t need them on my vehicles.

 

The front passenger tire was lower the last time TPMS values were set.

 

Hook up Techstream and get answers.

 

Get a manual tire pressure gauge.
Go to the closest gas station that has an air hose.
Bring all tires up to the proper pressure.
Reset the TPS system.
Go on about your day.
Simple.
Don't rely solely TPSM system alone.

 

Spare also has a TPMS as well, Correct?

 

I don’t think so, my 17 Sport doesn’t.

and the sensors only alert you when that particular tire is a certain amount lower than it was when set last. Just this week I had one tire that was yellow at 28 as it bounced between 27 and 28. Then as they warmed, it was normal at 28, before it went up to 29.

 

The reason not all of them alert you is when the TPMS sensors were "learned" they miight have been different pressures. The alert goes off when there is a % drop in tire pressure from initialization, not after a certain threshold (28psi). So once it drops 10% (don't quote me on the % decrease) from initialization, it alerts the driver. In theory if all 4 tires were inflated to 'exact' PSI and initialized at the same time, it should all be in the same. Hope that makes sense, I haven't had my coffee yet.

 

What the guy said above. Most systems look at the delta between the current reading and the reading when the system is reset

And who wouldn't want TPMS? Saved me several times. Picked up a nail. Tire started going low and the TPMS warned me. I carry a plug kit. Plugged it in a parking lot and ended up having a 20psi left in that tire and was able to get to an air station and air up and get on with my day. No dangerous blowouts or sitting on the side of the road. No tow charge or immediate tire purchase. No major time lost that day. Still need a gauge to set it up or check if there's an issue but I don't see a downside. And I'm an older guy.