Guys, as you know I've been running the 19" coupe wheels on my sedan and as a result I've got the TPMS light constantly on. Is there any way for a dealership or auto-shop to adjust the TPMS sensor to work correctly with the 19" coupe wheels?

Or do I need to buy an aftermarket kit?

Thanks

 

Your TPMS should work regardless of which wheels you are using them with. I swapped my original TPMS into a set of M45 sport rims no problem. Then I swapped them into a set of aftermarket rims, but needed a 90-degree adapter. No problem.

 

I was under the impression that the sedan's sensor was calibrated to the sedan's 17" tires & pressure and that swapping it for anything else would cause problems.

 

As you know, the TPMSs are calibrated so that the tire pressure light will turn on when tire pressure drops below a certain level - 26psi in my case (07 G sedan). Don't worry, you'll be fine (unless you like driving around on mid-20psi tire pressures for some reason).

 

Bring the car in and let Bernado take care of it. I swaped my '08 wheels with another set, and had to reprogram. same to all the cars I've sold at Beshoff Infiniti with aftermarket wheels, I always check to see if the TMPS has been taken care of. If not it, I roll the car to Bernado and he usally has someone quickly reprogram it.

Unless it doesn't annoy you if the light is on when you drive around. (I did that for a few months)

 

Thanks Dru - I think the problem is that I don't have any sensors on the vehicle, period. I didn't realize that I had to take them off the old stock 17" wheels & put them on the new ones (which didn't come with sensors themselves)

 

Why would you need to reprogram unless you had a brand new TPMS and needed to re-register? TPMSs can't tell what sort of wheels they are attached to. My original TPMSs (that came w/the 18" OEMs) work with my 19" M45 and 20" WORK wheels without having to re-register.

The procedure for the M might be different because I heard that each TPMS is registered to a specific corner (I do know the Ms get individual tire pressure readout, instead of only a tire pressure warning light), and you need to re-register even when you do a simple tire rotation.

 

To Answer your Question: Taken from http://www.aa1car.com/library/tire_monitors.htm

Pay Close Attention to ABS-Based TPMS Systems

DIRECT & INDIRECT TIRE PRESSURE MONITORS

There are essentially two basic ways to monitor tire pressure electronically. One is the direct method. A small pressure sensor is located inside each wheel. The sensor has a built-in transponder that broadcasts a radio signal to an external module. The module identifies the signal from each wheel and keeps an eye on pressure. If pressure drops below a predetermined threshold, the module turns on a light or displays a message to warn the driver.



The pressure sensors may be mounted in the drop center inside the wheel, or on the end of the valve stem inside the wheel. Stem mounted pressure sensors use the valve stem as the antenna, so don't replace the standard valve caps with anything else. Sensors attached to the rim drop center are typically held in place by a long steel strap that wraps all the way around the wheel. The pressure sensors are very accurate (usually within 2 lbs. or less).

The other method of monitoring tire pressure does not require any additional hardware inside or outside the wheel. It is the "indirect" method. This approach makes use of the existing wheel speed sensors in the antilock brake (ABS) system. By modifying the ABS operating software, the ABS system learns the average speed at which each wheel rotates when traveling straight at a constant velocity, and detects low tires by comparing relative wheel speeds. The auto makers like this approach because it is a simple, cost-effective way to monitor tire pressure. But it has some limitations.

On most North American indirect TPMS systems (1999 to 2003 model year applications), the systems cannot detect a low tire if two tires on the same axle are low, or if all four tires are low by an equal amount. But it can detect one or more low tire if the rest are at or near the recommended inflation pressure. Some of the newest European indirect TPMS systems can detect air loss in any combination of tires, as well as a gradual loss of air pressure during cold weather in all four tires.

Here's how the indirect ABS-based TPMS works. If a tire loses air, the diameter of the tire shrinks slightly causing it to turn at a slightly faster rate than the others. But on most applications, a tire has to loose anywhere from 8 to 14 pounds of air pressure before there's enough of a difference in diameter to be detected by the wheel speed sensors. It depends on the type of tires, tire diameter and aspect ratio, and the sensitivity of the ABS system.

Low profile tires with short stiff sidewalls change diameter less than tires with taller aspect ratios and more compliant sidewalls. Consequently, a loss of 10 psi in a low profile tire may only change the diameter of the tire less than 1 mm (0.040 inches). Most ABS systems cannot detect changes smaller than 1 mm. For this reason, indirect ABS-based tire pressure monitoring systems are not as sensitive as direct TPMS systems that have a pressure sensor inside each wheel.

ABS-based systems must also relearn the rotational "signature" of each tire when tires are replaced, repaired or rotated. It's also essential that the tires all be properly inflated before the recalibration procedure takes place -- otherwise the module won't recalibrate correctly and may not detect a low tire.[/SIZE]

Some vehicles that currently have indirect ABS-based TPMS include 2001 to 2003 Ford Windstar, 1997-2002 Buick Park Avenue, 1999-2003 Buick Century & Regal, 2002-2003 Buick LeSabre, 2003 Buick Rendezvous & Aztek, 2000-2003 Chevy Impala & Monte Carlo, 1999-2002 Chevy Alero, 1999-2002 Pontiac Grand Am, 1997 - 2003 Pontiac Grand Prix, 2000 - 2003 Pontiac Bonneville, and 2001-2003 Oldsmobile Aurora.







As for the direct TPMS systems, they have their own technical issues as well. One is battery life. The pressure sensor inside each wheel contains a small battery to power the sensor and transponder. Most are long-life lithium batteries that may last from five to 10 years. Eventually, though, the batteries will go dead. On the Corvette and Cadillac applications, the battery can't be replaced separately so the sensor/transponder must be replaced as a unit. If a battery has died, it's probably a good idea to replace all the TPMS transponders if the vehicle is more than six years old.

Another issue with direct TPMS systems is keeping track of which wheel is which. Rotating the tires obviously changes the location of each transponder. So the system must be reset so the control module can relearn the position of each transponder. This may require the driver to push a reset button on the dash or to follow a menu on the driver information display.

On some applications, the batteries are replaceable, but most are not. Consequently, most tire dealers will recommend replacing the TPMS sensors when the tires are replaced (typically after 5 to 7 years of service).

On the Corvette and Cadillac applications, each transponder is coded to a particular wheel. The pressure sensor only operates at speeds above 20 mph, and only transmits once per hour when the vehicle is parked to extend the life of the battery. If tire pressure drops below 24 psi or rises above 39 psi, it will trigger a message to be displayed on the Driver Information Center.

Relearn procedures vary quite a bit from one vehicle to the next. If the information is not in your owners manual, you can purchase a TPMS relearn/reset chart that covers most domestic vehicle applications from the Tire Industry Assn.. Click Here for information on how to order the TPMS reset chart.

 

This is what I got from quicky skimming the article.

There are 2 basic types of TPMS systems:
1) DIRECT (This type includes a pressure sensor inside each wheel), and 2) INDIRECT (This type does not include any pressure sensors inside each wheel. This is aka an ABS-based system).

The text which you HIGHLIGHTED IN RED specifically refers to ABS-based system aka indirect system.

Since since our G's (well at least for V36s, not sure about V35s, but from Calcul8's posts I assume it's the same) have a pressure sensor inside each wheel, by definition, this means we have a direct system, and not an indirect one. Therefore, the text you HIGHLIGHTED IN RED which pertains to an indirect system does not apply.

That being said, I will give you some benefit of the doubt because the article does state "[an] issue with direct TPMS systems is keeping track of which wheel is which. Rotating the tires obviously changes the location of each transponder. So the system must be reset so the control module can relearn the position of each transponder." HOWEVER, apparently this does not apply to all direct TPMS systems because I haven't heard of a single V36 owner (me included) that needed to re-register their TPMSs after doing a simple rotation. Although this does apply to Ms, so I've heard. Also, it seems the article was written around 2003. All things (especially technology) can definitely change a bit in 6 years.

 

I'll find more info to better answer the question. More updated for ya!

 

*Finished Googling*
There's alot about both sides, on this subject. not much updated information in any case. (Information that is verifiable on print to date) Experience really isn't hard proof, on my end. I only sold a few hundred cars.

The answer to all my problems when the TPMS went haywire, either with stock tires/rims or aftermarket is to have them reprogrammed.

Not too sure why but I swapped out my 17's to another set of 17's took the original TPMS and put them on the new rims, and still had to reprogram. then again my car is 2008 G35 might be different with the (different year/technologies?)

But as in for disabling it the light, (because there is no TMPS) Best thing to do is bring it in and have Bernado see if there is away to do that.