Due to these issues coming up right before a cross state move and the holidays, I haven't gotten around to addressing them yet. I do believe they may be related though, and wondered if anyone had a good suggestion on where to start looking.

One day I was driving down a highway and my TPMS indicated a fault with the system. Ever since then, the car shows the fault when started. I had just enough time before the move to take it into the tire shop, and they found the right rear tire sensor had a dead battery. They replaced it, verified they could read the new one with their tool, but couldn't get the car to clear the fault.

Around the same time, I noticed that my key fob had a significantly reduced range. I basically have to be next to the car, near the drivers door for it to work. At first, I assumed my battery in the key fob was the problem, so I replaced it. New battery, same poor range.

So now my theory is that there is an antenna, or antenna cluster of some sort responsible for picking up the key fob and TPMS signals. Based on where my key fob works, and the right rear tire not being detected, it seems somewhere near the drivers side front of the car. Anyone have any ideas on where exactly the antennas could be? I'd like to check if something became disconnected and cover any other basics before taking it into an unknown dealer in my new town.

 

It is in the smart junction box. I think it is located on the pass side kick panel.

 

I finally took the car into a dealership, figured I'd combine a maintenance trip along with a troubleshooting trip.

Thanks to 05blkvert's info, I found all the documents I could about the smart junction box (SJB), and did my best to verify all the connections. It seemed fine, and nothing really stood out, though I didn't dig too deeply due to how awkward it is to work in that area.

The dealer did ok (not great) on the general maintenance, but seemed to want to jump to "lets sell him a new part" mode regarding the issue. The service advisor told me they found out the SJB is defective, and a new one would cost $700+. Being that I have all the service documentation about the SJB and what it does, I found this a bit suspicious. So I asked what error code was received, and they couldn't provide me one. With an alert on the dash, I find it highly unusual that they would say the entire box needs replacement, without any code.

What I have found over time with the issue is that the system is still reading some of the tires just fine. If pressure is too low in the passenger front tire, it alerts properly. And everything else the SJB controls is working just fine. I checked online, and it looks like working condition SJB replacements run $135ish for the parts. Even with say 2 hours to install, at a very high $120 per hour, I can't figure out where they got the $700+ quote from.

Anyone have any advice, or experience with the same issue?

 

Don't forget the dealers have that book where they look of the largest amount of time they can stick you for , which usually has nothing to do with reality. Now that you know what it is , I'd call another dealer ship and ask what they charge to do the same thing. You don't even need to be in the same area , just say you are and you want an estimate before you set up an appointment ...

 

I have the same issue. Every now and then the key fob won't lock unless I walk back and stand by the door.

 

I'd check for moisture around the SJB. Also I think you can reset the TPMS alert with a tuner or an OBD2 scanner. There is a code also. There is a TPMS troubleshooting section in the service manual.

 

My 2007 V6 won't arm about every 5 times and I need to restart the car turn back off and then it will arm. new batteries in both fobs. Any ideas?

 

There is a coax antenna that plugs into the back of the SJB. Where it runs to I don't know, I have found no other info on it. I suppose it might run up the A-pillar. As mentioned in other replies check for moisture- water stains in SJB area. Maybe you should disconnect the battery, access and remove all SJB connectors and spray clean/blow dry connectors with QD contact cleaner.