I'll be brief:

- Had an '06 T5 with no TPMS issues
- Bought a '10 3.2, and the tires were garbage. The TPMS lights were on. I assumed it was the sensors. Mismatched tires, mismatched wear, etc.
- Swapped the wheels/tires on the two before selling the T5 (they were buying new ones anyway).
- Expected the T5 to have TPMS issues and the 3.2 to be cleared.
- Nope. The T5 light came on, then cleared once the sensors paired. The 3.2 continues to have problems. I assume it's the receiver.
- I've taken it to two shops so far (Les Schwab, and a local shop that I've used in the past) and both have looked it over and said "sensors are fine, it auto pairs, just drive it for 10 mins then let it sit"
- Infuriating, I can't get anyone to look at the receiver, and I can't seem to find it on any parts store.

Help appreciated. Best case, someone has experienced this and knows how to fix. Alternative, someone knows what the part is. I've avoided the dealer because of dealer premium prices, but that might be my last option at this point.

 

The receiver might be in the UEM (upper electronic module). It's a circuit board glued to the back of the inside mirror glass. The first step would be a scan with a compatible scan tool to see what codes are stored and where. An example of possible uem codes is below. Most tire stores have a hand held TPMS sensor checker. Hold that tool next to a sensor and the tool can tell if the sensor is transmitting. UEMs are "coded" to the VIN - meaning a used mirror/uem will not work. However xemodex can "reprogram" a used mirror to work in your car. Vida can't. TPMS failure is not a common failure according to xemodex - so not sure if this info is helpful or not. I'd bet xemodex could test your uem - but you have to ship to to them.

Many Volvos use a 30659715 receiver for tpms (and other things) mounted above the headliner. That part does not fit 04-15 xc90's

 

That explains why I couldn't find a part called "TPMS Receiver" if it's built into that upper module. As for the sensors, both shops scanned them and said they were transmitting and there was nothing else they needed to do. That's why I'm thinking that module or an antenna or along those lines might be where the fault is. My OBDII Scanner didn't find any codes I'm assuming that's what you meant by compatible tool. This is starting to sound like it really is beyond me or the tire shops to solve, and I should just take it in to the dealer. Or drive with the light on. I check my tire pressure regularly so might be where I end up. Thanks for the detailed answer!

 

An basic OBD scanner just checks for emission related codes in the ECM and TCM (trans and engine control units). A compatible scanner will scan all the control units shown in the network diagram below if installed in your car - you probably don't have PHM - phone, or GPS or AEM (aux) . You'll only have a HCM if your headlamps turn with the steering wheel. So you have 15 to 20 control units that can store fault codes and be accessed for other information.

If you take it to the dealer and they think it needs a new UEM - that's about $1000 in dealer language. (a mirror replacement plus a VIDA download to make it work)

 

Oh wow! This is so far beyond what I leaned in shop class 15 years ago, but I could put in the effort to learn to save $1000. I'll start by getting a tool that scans all the modules and see what codes are stored, then figure out what comes next. Any recommendations on scanning tools?

 

Your best bet is the free stolen/hacked VIDA 2014d easily found on the internet installed on your win7 pro cpu. A dice unit is used to interface between the CPU and the OBD port on your car. Here's a thread related to that

https://www.swedespeed.com/threads/v.../#post-8054525

 

the sensor in the tire has a built in non-replaceable Li battery that is good for about 10 years. After the battery dies this will need replacement the sensor is integral with each valve stem. So the tires need to be dismounted, maybe just one side and the new valve stem assembly installed. Go to a reliable tire shop or even Fleet Farm or the equivalent.