[HAQ]

Originally Posted by Cromartie84

My dash has been telling me that all four tires are low? Could all the sensors be bad at
The same time?

On mine if 2 are low then it shows all 4. Last month I had 2 down put air in one and it only showed my left front was low after that....put air in that one and I have been fine since.

[lacoa]

Originally Posted by Bimmer.335i.

i know 1000000% that the battery is not shot. its the tpms

You do realize that when we refer to the "battery" being low we are referring to the battery within the TPMS unit right? Please scroll back to my first reply in this thread.

[lacoa]

Originally Posted by Cromartie84

My dash has been telling me that all four tires are low? Could all the sensors be bad at
The same time?

And you adjusted and verified all tire pressures?

[fireline43]

did you install any angel eyes recently?

[lacoa]

Originally Posted by fireline43

did you install any angel eyes recently?

Interested to hear the correlation here....

[Z&M Auto]

Originally Posted by Bimmer.335i.

i know 1000000% that the battery is not shot. its the tpms

I've removed and replaced 100's of sensors. Never had a Beru sensor go bad unless it was physically broken during the demount/mount process. Its plausible just IMO unlikely.

The majority of sensors use 3 volt lithium ion batteries and some use 1.25-volt nickel metal hydride batteries. The "life expectancy" they expect from these things are usually 5-10 years (quite a range, I know) or about 100,000 miles.
Keep in mind tons of factors are in play. How many times the sensor is transmitting data to the ECU, and the climate. The batteries last quite a bit longer in colder climates.

But if a shop has the correct scan tool, they can pull the battery life from the sensor.

[fireline43]

Originally Posted by lacoa

Interested to hear the correlation here....

http://www.e90post.com/forums/showthread.php?t=741589

[Z&M Auto]

Originally Posted by Cromartie84

My dash has been telling me that all four tires are low? Could all the sensors be bad at
The same time?

Any specific time of when this happened? Key factor here is measuring the air pressure in all four and seeing if they are all the same. A reading of 25psi at all four or 25-26-25-27 is going to happen when it gets colder out for the first time. Every 10 degrees F equates to 1-2 psi of air pressure loss. If the car calls for 32 PSI and 34PSI in the rear and your have say, 30 and 31... the TPMS WILL NOT illuminate on the dash. "Threshold" pressures vary from 25psi to 27psi.

BUT, there is also the off chance of bad luck that all four tires have a puncture. Always need to have the tire checked for any cuts/punctures/bead leaks and sensor leaks. Sneaky and hard to catch leaks sometimes occur from the grommet seal on the actual TPMS. Just a tidbit of info, ANY shop that wants to replace a sensor on these cars because of a leaking grommet, kindly tell them to go screw themselves, and take your business elsewhere. AFAIK, 07-09 sensors use a two piece sensor. The stem attaches to the sensor. All that needs to be replaced in the case of a leaky grommet/seal is the grommet kit. If the stem is stripped, then all you need to do is remove the sensor, grind the old stem out from the bottom, and replace with a new stem that can be had for $20 bucks.