TPMS woes

[elc32955]

My TPMS system is recently started acting up and it's starting to drive me crazy! I keep getting the 1000 cps warning chime and warnings for low air pressure on my tires, except that it's erratic and intermittent. Two tires (example - LR and RR) can show the exact same pressure (example - 34 PSI), the LR will throw a warning on start-up, the RR won't. Or they both will, or neither will.

I know this has probably been covered a million times in different forums, but is anyone else seeing the same issues I am? It may be dealer time.....

Eric

[gregc]

I haven't had issues with mine. But I only have 2500 miles on it. I put brand new TPMS on my Camaro rims and left the originals in the PPV rims. Did you remove the TPMS off your old rims and reuse them for your new rims?

[elc32955]

Yes. They came off the steelies and were placed onto the G8 rims. Direct interchange from all indications. They worked fine for some time, just this last two months they've been starting to go bonkers. I had attributed it to cold weather and tire pressure changes, but now I'm not sure at all...

[gregc]

Yes. They came off the steelies and were placed onto the G8 rims. Direct interchange from all indications. They worked fine for some time, just this last two months they've been starting to go bonkers. I had attributed it to cold weather and tire pressure changes, but now I'm not sure at all...

When I had my tires put on, the installer wanted to charge me for a TPMS rebuild kit, which is half of the system. The part that goes in the rim stays, the valve stem part is supposed to get replaced. Since I bought an entirely new TPMS, I didn't need the rebuild kit. Have you put enough miles on it to recalibrate?

[elc32955]

I think the pressure readings are accurate, it's just triggering the stupid dash alarm. Wonder if there are setpoints that can be altered in the BCM that manage this function. I was thinking if other people have had this problem there might be a TSB out covering it somewhere.

Car has 18K and change on it right now. I could probably get the dealer to try to recalibrate, just trying to avoid dismounting the tires since the rims on the car are not original and I think they'd probably charge for it (even though they are GM rims, well G8 rims anyway).

[gregc]

You may need to reset your TPMS. Here's what I found about mine. Since Pep Boys installed my tires on the rims, but not on the car, they didn't program my TPMS. After driving to the muffler shop to get my exhaust tips installed, my TPMS warning light came on and the dash said TPMS fault. I looked in the manual to see how I can clear the code. It said you have to reprogram the TPMS with a TPMS programming tool. Since I don't have such a tool, I took it to Pep Boys and had them program it free of charge since they mounted the tires on my wheels. Each TPMS is specific to the location of the tire, LF, RF,RR and LR. So if you rotate your tires, you have to reprogram your TPMS so the vehicle knows which tire's tire pressure. You can also buy the tool on ebay. It's $80. Part number is EL-50448

Even if you have staggered tires, the car will know the fronts from the rears as long as you program the TPMS in the right order. You have to start with LF, RF, RR, and LR.

You used to be able to reprogram the TPMS by going into the programing mode, then deflate your tire till the horn beeps, but GM changed the method to reprogramming the TPMS because it was picking up the TPMS signal of another car in close proximity. The TPMS works by sending radio radio signals to the BCM

[elc32955]

Just a little update on this, I decided to do an experiment. I pumped the tires up to around 40 PSI warm, the TPMS says they are between 39 and 41 running down the Interstate. But, all the warnings finally quit!

I think our TPMS programming just doesn't like any tire pressures under 35 PSI for some reason. Given that down here we always pick up 2-3 PSI when the tires are heated, this puts me at 38 hot if I'm running 35 cold. Weird the way the alarms trigger, one 34 PSI reading will trigger an alarm condition and another on an adjacent tire won't.

[storm9c1]

Just a little update on this, I decided to do an experiment. I pumped the tires up to around 40 PSI warm, the TPMS says they are between 39 and 41 running down the Interstate. But, all the warnings finally quit!

I think our TPMS programming just doesn't like any tire pressures under 35 PSI for some reason. Given that down here we always pick up 2-3 PSI when the tires are heated, this puts me at 38 hot if I'm running 35 cold. Weird the way the alarms trigger, one 34 PSI reading will trigger an alarm condition and another on an adjacent tire won't.

Yes, mine does this too. I keep them above 35 cold. Which quiets the alarm. I noticed that if multiple tires get too low at the same time, only one tire will show alarm unless another tire falls significantly more. But it's kinda random... I also noticed that once the alert is triggered and the tire heats up and the pressure goes up a PSI or two (to 35), it still won't reset. I need to add a few PSI of air to make it happy. So there must be a hysterisis involved.

Keep in mind that factory spec pressure is like 42psi or something (recalling from memory). Look at the sticker on your door jamb. The factory spec is too high for me. Bumps are too rough (wasn't the suspension softened for the 2012 model year?). So I keep mine lower than spec to smooth the ride a little.

[leadfart]

Mine like to beep at around 32. I've found 38 all around is an acceptable compromise for me. I bought one of those tire pressure reset tools, off the internet. Really cool to have on hand.

[Navy Lifer]

The factory spec is too high for me. Bumps are too rough (wasn't the suspension softened for the 2012 model year?). So I keep mine lower than spec to smooth the ride a little.

Springs are the same, but shocks changed for 2012 & later.

Owner's manual says 36 PSI at all positions for "normal" (non-full load or high-speed) use.