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[Surly73]

Hi:

I have a new-to-me 02/2007 build 328i 6MT sport/premium and I'm in the midst of figuring out things that, er, aren't quite like the previous owner said/thought they were.

The option sheet for my build doesn't say one way or the other how the car is equipped. Here's the situation and conflicting info I see:

• The PO specifically talked about TPMS sensors and the fact that they are also installed in the winter package he included with the car (which turns out to be an E46 set and he didn't include or appear to use spacers, but that's another story)
• The owner's manual shows both FTM and TPMS as (*) options. The book says resetting the BC for FTM will display "INIT" and for TPMS will display "RESET". My car says "RESET" - leads me to believe TPMS. See pages 65-67 of this.
• I've seen it stated here and elsewhere that TPMS sensor equipped wheels have metal valve stems because they are actually part of the sensor. All 8 of mine have plain rubber stems.
• I've seen it posted that TPMS didn't start until 03/2007 (like here) but I know that cars near transitions like this can come either way.
• There seems to be no function to read individual tire pressures which would be conclusive. As I understand it, TPMS sensors require wheel rotation for power so BOTH FTM and TPMS would only work while rolling, and BOTH are only capable of telling me that something is wrong with one of my tires without being specific about pressure or which tire.

So, maybe I'm wrong and the sensors are battery powered. Would I then be able to simply let half the air out of a tire with the car running and if it's TPMS it will throw an alert and if it's FTM it won't until I drive on it? Has anyone with true TPMS seen a low pressure alert without having to move the car?

Is there any other way to be sure without dismounting a tire to look for the module? Could regular rubber stems have been fitted to the sensors?

EDIT: TireRack says that TPMS compatible rubber stems have also been used starting in 2007...

[Tom K.]

[quote=Surly73;11934109]Hi:

So, maybe I'm wrong and the sensors are battery powered. Would I then be able to simply let half the air out of a tire with the car running and if it's TPMS it will throw an alert and if it's FTM it won't until I drive on it? Has anyone with true TPMS seen a low pressure alert without having to move the car?[quote]

I'm sure my late (export date 8/16/07) 2007 wagon has TPMS and it did throw a low pressure warning without the car being moved. The car had been parked overnight and a nail had caused a front tire pressure loss from about 34 psi down to 30. Although I did change the dealer set 40/40 inflation back to the 32/39 recommended, I luckily had never reset the TPMS so I got the warning without driving the car with less than 30 psi. (Apparently the TPMS threshold is about 20~25% under the set pressure.)

So, as your analysis seems to me to be very incisive, I suspect your experiment is worth trying. If you don't get the alert, try shutting the ignition off and then re-starting.

Tom

[bavarianx]

There are other ways to tell besides taking the wheels apart. Easiest way is call the dealer with your VIN and ask them if your car has TPMS.

[Gary@TireRack]

Originally Posted by Surly73

[*]I've seen it stated here and elsewhere that TPMS sensor equipped wheels have metal valve stems because they are actually part of the sensor. All 8 of mine have plain rubber stems.

This is the only info needed to answer your question. If you have rubber stems as OEM and are getting no errors, you have FTM.

[Surly73]

Originally Posted by Gary@TireRack

This is the only info needed to answer your question. If you have rubber stems as OEM and are getting no errors, you have FTM.

Well, I have no idea (and highly doubt) that the valve stems are OEM. The PO seems to have taken care of the car, but wasn't particularly fastidious about always doing everything "right". I have no idea where he may have had the current tires mounted but I bet it wasn't the dealer.

Originally Posted by bavarianx

There are other ways to tell besides taking the wheels apart. Easiest way is call the dealer with your VIN and ask them if your car has TPMS.

I've pulled the build and option sheets and they don't list it as an option. If it's a matter of build date cutoff my vehicle is right at the cutoff and whatever they look up may be in error. I've had BMW's built near minor change dates before (like changes to the serpentine belt system) and they weren't built with the parts that the dealer computer thinks they were. I had to look at the actual car to know which version to order.

I guess maybe I'll have to try driving around the block (to make sure that the TPMS senders are "awake" and have transmitted) and then let half the air out of a tire. If it pops a warning while stationary then I have TPMS. If not, then I probably don't have it (and the PO is very confused about having sensors in all of his wheels). He's got no reason to lie about having sensors - it's not like it was part of price negotiations or a "must have" feature from my side. Of course maybe the car has FTM and the PO wasted a lot of money on sensors he didn't even need.

EDIT: The RealOEM page for TPM parts says "no parts matching your car" so RealOEM believes I don't have it. That's consistent if 3/2007 start date is 100% accurate without exception (I've seen it be wrong before). BC says "RESET" and not "INIT" (points to TPM) and the PO went on about sensor. Will try the test and see. In a lot of ways I'm not sure that I care one way or another. It's less expensive for me in the long run if I don't have TPM and I need to know if I need to budget for and buy sensors if/when I get a new package.