The title speaks for itself. I noticed that my left rear tire was at 25 psi (when it should be at 33 psi) but my warning light did not go off. Does anyone know what's wrong, if anything? This is on the stock 18" wheels for the sport package sedans if that helps.

UPDATE:
The sensor is fine. I released it to 20 psi and before I was able to shift it in to reverse, the warning came on. Thank you guys again for your help and suggestions!

 

If your car is still under warranty the dealer should be able to replace the sensor(s), that's probably what it is. If it's out of warranty take it to a tire shop, they will have the equipment to take care of it.

 

Oh Okay. I thought there would be a warning light if there's a sensor malfunction. Which warranty would the sensor fall under? My car has 49k miles.

 

To be honest I'm not sure if a bad sensor would keep the TPMS light off during a low pressure issue, but would seem to be a sensor problem if it's not relaying that info to the ECU.
Like I said, if you still have warranty left I'd take it to the dealer (after you fill your tire, lol)

 

Yeah. I'll go get them checked out. Thanks for the help!

 

an 8psi difference in tire pressure probably will not set off the malfunction light on the dash. i would check if you have a puncture in the tire before taking it in to the dealer. if you really want to check if the light works when the tire pressure is low i would release the air down to 10 psi and drive it around the block.

 

Maybe it depends on the year, but in my 09 under 30 psi would set off the light???

 

It may take a larger deficit to trigger the warning light. I don't know if I've seen anything authoritative that tells you exactly when the indicator will be triggered. I've heard 25% low. I've heard 10 PSI low.

From personal experience I've not had it come on unless the tire was very low. I've checked pressure and found it as low as 26 or 27 with no indicator triggered.

If the TPMS is damaged I think it's supposed to illuminate and flash for a minute or two when the car is first started. I think.

 

There's a leak somewhere. I might try that out to see if the sensor is fine, crookncastle. I thought the warning would flash if there was a malfunction too. There's probably nothing wrong with it, might just be due to it not being in the range for the warning like you guys said.