awdinut

today I took apart a TPMS sensor to check the condition of the battery and see if I need to put in new batteries. I am changing wheels and I don't want to buy the new valve stems required (at $22 ea) and transfer the sensors if they are at the end of their battery life. I have an 04 and by everything I read the battery life is 5 years so I expected the 3.5V baterry to give a low reading. Instead, I got a reading of 3.65V which I would expect of a new one. Maybe the sensors have been changed before I got the car 6K ago.

Anyway, I soldered the connections back together and will seal the unit up and install the sensors and see if everything works. The point of this post is to say that the sensors can be disassembled and the battery replaced if needed.

theanimala

Would you mind posting the details on how to do this? I fully expect mine to fail sometime in the next year, and I would love to be able to replace the battery vs the entire unit.

mystrodo

All for the want of a digital camera.... which are cheaper then the sensors

skl1

My '06 SWB sport with 52K miles gives me a tire pressure monitor failure message almost every time I drive it and gives me the little flat tire icon... then it stars to work again half way through the drive... is it telling me the batteries in the sensors are going south??

theanimala

Yes. My car only does this when it is cold. Last winter it happened almost every day, then nothing for 9 months. I fully expect to hear this nonsense in the next few weeks.

davie

Mine was doing the same thing and the dealer had to reload the MMI software. It would fault just about every other day until they did this.

Edd W

It is possibly as the batteries are cold the voltage is too low to operate the sensor properly.
Do you know if tyre compound has any detrimental effect on the sensors ability to communicate with the monitoring system?

Mister Bally

I broke the LCD screen on my digital camera a couple of weeks ago on a flight. Do not keep a camera in your pocket when sitting on an airplane. When your leg slides under the armrest and you lift it up; crack!

Oh for the want of only $200 for a Kodak which work perfectly fine for me. My cam,era still works but nothing other than basic photos since I need to see the LCD display to change any settings.

Brozee

Yes, please post a how to on replacing the battery. On occasion I get the TPMS fault error and I just cycle the igniton or re-initialize the wheels and it works perfect. I hate the TPMS. lol

ghibliss

I just had my dealer replace 3 of the sensors on my 2004 A8L. Fortunately they were covered by the dealer under warranty as I had just recently purhcased the car from them.

Did you happen to take any pictures of the disassembled sensor showing the battery? Do you have any information to provide on the part number and style of the 3.5 volt lithium battery used in the sensor? What is required to disassemble the sensor to replace the battery? You mentioned that the batteries are soldered in place so I am assuming that the cells have solder tabs on them.