GM Volt Forum banner
1 - 20 of 39 Posts

·
Registered
Joined
·
104 Posts
Discussion Starter · #1 ·
I posted a thread a couple of days ago after I found out about my local chevy dealer refusing to fix an issue with the Tire Pressure monitor. They claim that my 18 months old window tint is blocking the signal. Today I was going through the paper work they gave me after picking up my car and I found this notice.

See the picture...
Text Document Paper Font Technology



After reading this sounds like they are implying that I voided my TPMs warranty just because I installed tint on my car...
 

Attachments

·
Premium Member
Joined
·
14,156 Posts
I have no issue with the document you posted. You can't alter equipment, have it fail, and then get GM to repair it. However, if the equipment has nothing to do with the failure, then the warranty isn't affected (the doc actually implies this).

I endorse Mike's suggestion of opening the windows. If the windows are down, and the problem exists, then the windows are NOT involved with the TMPS and the dealer should fix the issue. On the other hand, if it works with the windows down but doesn't work with them up, then the tint is interfering with the wireless messaging and the dealer is right.

That seems like a simple enough experiment/demonstration. Have you tried this?

No idea BTW whether the TPMS system uses RFID or not. I know some do.
 

·
Registered
Joined
·
2,867 Posts
What's in the window tint, lead? Other than that, I cannot see how it would affect the communication with the TPM sensors.
 

·
Registered
Joined
·
14,024 Posts
Oh no!!! They are going to void my warrantee because I added a voltshelf II and a rubber trunk liner. Plus my sunglasses in the dash compartment is sure to wreak havoc with the remotes. I even waxed my car with non GM approved wax!!! I wonder what they will do when I plastidip the entire car in deep purple. What about all the folks who do wheel and suspension mods?

Seriously, we just need to get to the bottom of whether windows down still causes TPMS issues. This sounds fishy to me.
 

·
Registered
Joined
·
14,024 Posts
I wouldn't even expect the signal path to be through the windows. I'd expect the antennas would be in or near the wheel wells.
Somewhere I read that the antenna is in the little black box behind the rear view mirror. So there may be some validity to the window tint blocking the signal. I used to manage a team of computational electromagnetics PhDs working primarily radar, but these guys would be able to figure out whether the 315 MHz signal could be blocked by window tint. Heck, we could even create a CAD model of the vehicle and simulate it using https://www.leidos.com/products/software/antfarm/ or http://delcross.com

Alas, we'd need the material properties of the window tint to be able to do the simulation. That said, it is plausible that the dealer's claims are true. But from what I've absorbed through osmosis working with these guys is that high frequency signals are very directional and can be affected by blockage and scattering while lower frequency signals (which this is relatively low) can work their way around objects with creeping waves. The metal sides of the vehicle itself is probably doing more blocking than the windows. The wheel well are plastic which should allow the signal to penetrate, but I'll bet the firewall is another major blocker. It's possible that the GM engineers are depending on the windows to get the signals from the tires to the receiver. Since the TPMS is operated by batteries, the signal has got to be very weak and only needs to transmit periodically about 4 to 6 feet. So it wouldn't surprise me if the dealer is right.

It all comes down to lowering the windows for a few weeks and seeing if the problems disappear.
 

·
Registered
Joined
·
2,360 Posts
Somewhere I read that the antenna is in the little black box behind the rear view mirror. So there may be some validity to the window tint blocking the signal. I used to manage a team of computational electromagnetics PhDs working primarily radar, but these guys would be able to figure out whether the 315 MHz signal could be blocked by window tint. Heck, we could even create a CAD model of the vehicle and simulate it using https://www.leidos.com/products/software/antfarm/ or http://delcross.com
More than likely an RF interference issue rather than tint affecting the TPS signal...
 

·
Registered
Joined
·
14,024 Posts
More than likely an RF interference issue rather than tint affecting the TPS signal...
It could be RF interference. So does the original poster have any cheap Chinese USB chargers or other devices plugged into the 12V adapter?
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #13 · (Edited)
It could be RF interference. So does the original poster have any cheap Chinese USB chargers or other devices plugged into the 12V adapter?
Interesting point. Are you the person who worked on my car? How do you know I have a cheap chinese charger... LOL. ... good point I will remove it and try again...

I have to ask the question. Looking that you are from IL and actually the dealer also printed a Posting from this Forum and attached it to my paperwork. Showing me other conversations about window tinting. I'm guessing some of the member here are actual people who works at the dealer. ANd possibly the guy who printed that page for me.

But if they know that Cheap devices could cause interference then why they blame on my windows tint....

Anyway... Thanks everyone for your input.. I will take my car to another dealer or just pay to replace the TPMs at a local tire store... It worked 18 months since I had my tint installed... What could happen another in 18 months.
 

·
Registered
Joined
·
409 Posts
Do you have a metalic tint? There are 3 main types of tints I know of. Dye which is just color and will not cause a problem. Ceramic which blocks out some of the heat, its expensive and will not cause a problem. Metalic which also blocks heat, is not as expensive as ceramic, BUT it can interfear with the cars electronics. I don't know about a metalic tint in relation to the warranty, but it could create your TPMS problem.
 

·
Registered
Joined
·
92 Posts
Try the suggestion of the windows down test before you go to another dealer or replace the sensors. That will really help prove whether the tint is affecting the system by blocking the signal. Is your tint metallic?
 

·
Administrator
Joined
·
22,242 Posts
Try the suggestion of the windows down test before you go to another dealer or replace the sensors. That will really help prove whether the tint is affecting the system by blocking the signal. Is your tint metallic?
This was also suggested in the OP's original thread, and yet again here. Seems odd to keep hashing this out without trying this simple test.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #17 ·
This was also suggested in the OP's original thread, and yet again here. Seems odd to keep hashing this out without trying this simple test.
If the issue is permanent then opening the window is the best troubleshoot option.

In this case The issue is intermitente and only one wheel, right rear. It lost connection at highway speeds after 10 or 20 minutes drive. It last for few minutes specially if I get out of the highway it goes back to normal. I also noticed tire pressure readings varies a lot during my commute of 40 minutes. Not sure if this is normal. But it goes From 35 to 40 psi . At City speeds everything is ok. Is more repeatable when the weather is hot. Here in Chicago the weather has been varying from 88 a week ago to 38 like this morning. Yesterday was ok whole day since the weather was mostly sub 50s.
 

·
Registered
Joined
·
6,677 Posts
Maybe I missed it but how many TPMS are not registering? One, two or all four? If any are registering than I think we can eliminate the window tint. I lost one sensor on my 2012 and once it was replaced it's been trouble free ever since. And when I was shopping for window tint I made sure the manufacture LLumar stated their ceramic tint wouldn't interfere with any electronics.

Good luck.
 

·
Registered
Joined
·
104 Posts
Discussion Starter · #19 ·
Maybe I missed it but how many TPMS are not registering? One, two or all four? If any are registering than I think we can eliminate the window tint. I lost one sensor on my 2012 and once it was replaced it's been trouble free ever since. And when I was shopping for window tint I made sure the manufacture LLumar stated their ceramic tint wouldn't interfere with any electronics.

Good luck.
From what I know is only ONE giving me the issue. Here is the picture I took a day after the dealer did a re-calibration. The dealer said there are 3 sensors having issues connecting due to this they are blaming the windows tint. I haven't seen all three sensor going out but only one... As I said the issue is intermittent. I wish it stays on so it would be easier to trouble shoot.
 

Attachments

·
Registered
Joined
·
115 Posts
What brand/type of tint do you have? IF that is the issue, I would assume others with the same tint would be having issues as well. Ask the dealer that if you remove the tint, and the problem still exists, would he then fix it under warranty and pay to have your car retinted.
 
1 - 20 of 39 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top