So usually all my tires are at around 31PSI - 33PSI. I happened to pull in a parking lot today after some driving and I get a "check tire pressure" from MID for the front left tire. Immediately I look for the readings for all tires from MID and the front left is at 27PSI while the others are at 34PSI. Came out the car and went to check out the tire. As I get close enough to it I can hear air escaping the tire...so I pretty much have a slow leak. Went ahead and put on the spear and there's a big screw right in the middle of the tire! I'll have Costco patch it up tomorrow since I did buy the tires from them (Michelin Pilot Sport A/S). I was so happy that the TPMS told me my tire was getting that low...very safe and reliable system!

OK, so now I'm getting a TPMS system error after the spear's reading was 58PSI. I kinda expect bogus reading for the spear since it doesn't have a sensor on it, but I'm concerned about the TMPS system error message. Should I be?

 

no.

 

You should also disable the VSA when you drive with the compact spare. You will have to do it each time you turn the ignition on. It's in the owner's manual.

The reading for the spare appears to be correct, but I don't know why you got that reading without a sensor (unless the spare also has a sensor in it). Normal pressure for the compact spare is around 60psi.

 

I think you're getting the "default" reading for the wheel with no sensor. When you put the repaired tire back on all should be normal.

I agree- TPMS saved me once as well. Same issue- drywall screws in the rear tires.

 

Will the TPMS ever state that you have a flat? Or just read PSI as being low?

 

Question about Costco tires. When you get tires from costco they give you new stems and the green cap but I like the silver stem that the TL w/ TPMS comes with. Do they keep that if you get tires from there or is there a difference? It's just cosmetically I like the silver stem and cap better than the black and green.

 

the TMPS does work great and saved me a few times over the last month (3 seperate flats) - on the tire that was completely flat it did read 0 while the other 2 were slow leaks that just showed low pressure - I freaked out too over the 58 reading on the spare until I realized what it was - as soon as a regular tire is back on it will be fine

 

I would suppose that the tire that you took off and put in the trunk would still be sending a signal to the TPMS, just the same as if it was on the car. I have not looked at my car but I suspect that the spare would not have the TPMS on it.

 

Glad the TPMS help you out. However, you should know that the pressure isn't supposed to be the same front and rear. Check your manual or door post. On mine it's 35 frt and 32 rear. It was delivered 33 all around and there was a noticeable improvement when I increased the front. Try it.

 

The spare does not have a sensor. The light is on because the sensor is no longer registering with the computer.

The sensor on the rim in the trunk cannot be picked up by the front transponder.

If you look at the TPMS display, you should notice a vertical white bar on 3 of the 4 wheels. This is telling you that the computer is getting a signal from these 3 tires. The 4th where the spare is should not have the white bar, indicating that the sensor has 'failed'.

Because the sensor is part of the valve stem, I would kick Costco's butt if they took it off and put some stupid POS in it's place.

BTW: the computer is located behind the rear seat back on the driver's side. The transponders are in each wheel well.

 

Good info.

But I remember the day, I check my tires to see if it is felt and I still do now with my 05 TL