TEF

Yesterday, I encountered the following TPS problem with my '08 Boxster S: Upon start up, a message appeared stating that the left rear tire pressure was four pounds low. Upon checking with a tire gauge, the pressure was at the correct 37 psi. I then reset the TPS function by putting it into the "learning" mode. After a short drive, all was well. Upon the next start up, a message appeared saying that the left front tire was four pounds low. I reset the TPS function by way of the "learning" mode and the problem went away until the next start up. Upon the third start up, the right front tire read four pounds low and I repeated the process. My assumption is that the next start up will involve the right rear tire being four pounds low.

My initial thought was that the TPS unit in the left rear wheel was defective, however, the problem seems to be moving to each TPS in sequence, so it's doubtful that all of the sensors failed in some sort of order. Therefore, I am wondering what the problem might be. For example, it it were the receiver, than why do any of the TPS units work and why can they be reset? If the problem were corrected by just installing four new TPS units, I would do it. However, it would be useful to know what the correct solution might be before engaging in useless (and costly) attempts to fix the problem.

Thanks in advance for any ideas on what the problem might be.

tomhartzell

How old are the TPMS sensors? If they're the originals, it may be time for new sensors. My understanding is that while they will often last longer, the expectation set is that they will perform for five years.

TEF

I am the car's second owner and they appear to be the originals, so you may well be correct. Today, after the third reset, I have not encountered a fourth episode that I assumed would have involved a crazy reading from the right rear sensor. Therefore, the TPS false readings might increase as they age. Anyone have luck with the Huf brand replacements? The appear to be cheaper than OE Porsche ones and claim to function as well.

danschy

It seems really unlikely that at least 3 of the sensors would virtually simultaneously stop working due to low batteries. Some people have reported issues with master unit and have had to replace it. If you can get your hands on a Durametric the battery levels can be read. I believe Huf is the OEM supplier and are considered a safe bet, but there a much cheaper options if you look around. Also, when I replaced mine about 4 years ago I found a place that would just crack the bead to install the new TPMS, so no tire dismounting or re-balancing was required, and it only cost $20 per tire. I think the TPMS's cost around $45 each - don't recall the brand - but it was not Huf.

danschy

And I'm pretty sure you do not have the originals - I've never heard of them lasting that long. I looked at a few 07/08 Caymans in 2014 when I bought mine and ALL had dead TPMSs. (And yes, all the owners told me they were probably fine, just needed to be reset at the dealer. )

TEF

I don't know how long they're supposed to last in a Porsche, but the TPM sensors in my 2004 350z have functioned without issue for 15 years. I can state this with certainty since I bought the car new in 2004 and have never changed them. BTW, I've found a Titan brand TPM sensor online for $35.00, does anyone know if these are any good?