I seem to remember this as well, so I looked it up.Fformula88 said:I am not up on all of the latest laws, but didn't the government mandate that new cars will soon need to have onboard tire air pressure monitors?
If so, the Solstice will need such a system. Would this work through the DIC on the dash?
Thanks for doing the research on it! Then I guess we are not likely to see such a system.rlhammon said:I seem to remember this as well, so I looked it up.
More there than you'd want to read unless you make these systems, but I didn't see anything that stated an implementation date. Also, FMVSS #138 does not appear in the current release of regulations, so it's not active at this point and will not be required on 2006 model year cars.
The car I happened to be referring to in my last post was my Olds Alero. I never saw it give a false reading. I found that it was set for a 10% differential, and it looks at average rotational speed. So... many people who don't pay attention to the tire pressure will have tires around 30 psi, and when one hits 26 - 27 the light goes off. If you get out and look, you don't notice anything... but if you take a gauge to the tires, you'll see the light was correct.slowandlow said:i have one on my alero sort of it mesures the amount differance between the tires rotation and if one is different from the other it goes off it is very stupid and gives false 99.9% of the time.
This makes NO sense to me at all. The sensor is not inside the tire, at least not on any system I've seen recently. That makes no sense at all from an engineering stand point either.dls6774 said:Autoline Detroit just did a segment with a guy whose company develops the tools the dealerships use to diagnose and service vehicles. He was saying that they were developing (had developed?) a tool so that when tire pressure monitored tires were rotated the mechanic would be able to set the system so it would know where the sensors were after the rotation. Are the systems more complex now or has it always worked that way?
I've never had a vehicle with tire pressure monitoring so this is all new to me.
So if I rotate my own tires, I'll just have to remember that that low pressure light I'm getting for the left front tire is really the left rear tire? Or buy the tool to reset the sensors myself? Or take it back to the dealer and for a nominal charge they'll reset them? Interesting...
Actually, this is exactly the case for the Corvette, and the XLR. Each wheel has a sensor/transmitter on the valve stem inside the wheel that transmits the tire pressure to a receiver in the car. Each wheel and tire is specific, esp. for directional wheel patterns (and asymmetric tread and tire directional rotation, plus the F&R different sizes...), and each transmitter has a different frequency.rlhammon said:This makes NO sense to me at all. The sensor is not inside the tire, at least not on any system I've seen recently. That makes no sense at all from an engineering stand point either.
Your Az uses the wheel speed sensors from the ABS. I'm 90% sure of it.AztekzRpurty said:I have the low tire warning on my Aztek. I would assume it will be the same as the one on the Solstice, if offered. It alerts through the DIC, and does not say which tire. It only false alarms after tire changes, or after you adjust the air pressure in the tires. All you have to do is hit one button to reset. It has been helpful on several occasions.
I had wondered how it worked, I knew there was no way for a sensor in the tire/wheel to be connected, so I thought maybe there was some feedback from the shocks. The abs feedback makes much more sense.
Okay... This might be starting to make sense to me... I've seen pictures of valve stems with little black boxes on the inside ends. They'd need to each transmit pressure on a seperate frequency and the receiver would know by the frequency which tire it was. Then if the tires got rotated (for those that can be), the receiver would have to be 'set' to the new location for each frequency. Interesting.solsticeman said:Your Az uses the wheel speed sensors from the ABS. I'm 90% sure of it.
Most cars with run-flats OEM must rely on the transmitter-type, because of accuracy and the fact that run-flat properties don't change as drastically with a 15PSI pressure loss when compared to a typical, non-run-flat tire.
Once again it's confirmed I don't know everything!! Thanks for that tidbit Solsticeman. For something along the lines of the Vette, XLR, etc... a car which you can't rotate the tires, that does make sense. On a car such as the Solstice, where you'll want to rotate tires (if you happen to slip the clutch by mistake and light the rear ones up now and then... but I'm sure none of us will do that) it certainly doesn't make sense. Especially on a low cost car...solsticeman said:Actually, this is exactly the case for the Corvette, and the XLR. Each wheel has a sensor/transmitter on the valve stem inside the wheel that transmits the tire pressure to a receiver in the car. Each wheel and tire is specific, esp. for directional wheel patterns (and asymmetric tread and tire directional rotation, plus the F&R different sizes...), and each transmitter has a different frequency.