Tire pressure readings are correct on three tires except the left front. Left Front just started reading wrong. Usually reads 18# when actual tire pressure is 30#. I've tried deflating and reinflating to 40#. No luck. Tried driving a few slow miles on run flat and than reinflating back to 40#. No luck. Hit reset button. No luck. I suspect the sensor at the tire is the problem. Any ideas on how to fix? Where is the sensor located? Can it be replaced or cleaned?
Chuck

 

The tire pressure sensor is integral to the valve stem assembly. It's just inside the wheel at the base of the valve stem. Depending on your year model, the cost of a new one ranges from about $70 - $100 or so. I've seen various things on ebay where someone sells rebuilt ones, but have not been daring enough to try that on my own. Also not sure how long a rebuilt one would last - maybe someone else could advise you on that. personally, any time i've had one acting weird i've went ahead and replaced it with a new one. One time i had one that kept saying the tire was flat, then for a while it would be ok, then it would say it was flat again.

Luckily the only times i've ever had to change one of these it was time for new tires anyway, so saved a few dollars on remounting and balancing the tire, as the tire has to come off to install the new valve stem/sensor from the inside of the wheel. Another thing, if/when you do get a new one installed, your DIC will read as if you have a flat and/or need tire pressure monitoring system serviced. Don't freak out, that is normal. You will have to reprogram the wheels, but its really quite simple. Here's how you do it:

press the options button several times until there is no text at all on the DIC

press and hold the reset button for a few seconds, "key fob training" should suddenly appear. if you then push options it should go to the "tire training" mode. ( i can't remember, but you may have to push options one more time to initiate the training).

then, the DIC will tell you which wheel to train or reprogram first. to do this you either need the special tool that gm has, or do i like do and use an old speaker magnet! just hold the speaker magnet around the valve stem of the wheel that the DIC tells you, and wait for the horn to honk. Then look at the DIC and go on to the next one.

its really quite simple. do notice though, every time i've had to reprogram one wheel i've actually had to do all four, i'm guessing the computer won't let you skip to just the one that was replaced.

anyway, hope all of this helped. good luck.

 

Thanks mriley. I'll try to reprogram first than look into buying a new sensor. I'll let you know if i've had any sucess.
Chuck

 

mriley,
Didn't buy new sensors but I tried reprograming each tire with the existing sensors in place. The proceedure worked as you explained except the faulty reading went from the L FNT to the R FNT and now the L FNT reads correct. Go figure! I read in another forum that the sensors have a battery imbedded in them that last about 7-10 years. If thats true than the other three sensors will go soon. Anyway I'm not going to spend $300-$400 to replace them all. I'll just have to get used to checking the tire pressure myself from time to time unless someone has another idea to explore.
Chuck