Thanks SilberGrau, I had understood what you wrote as well until a BMW engineer who visited my dealership some years ago disputed that belief and explained it to me differently. He stated that the tire pressure monitors are basically all the same in all cars. Different designs, different frequencies. They all measure actual pressure. The cars electronics uses the info differently. Your explanation makes more sense. But whichever way it works, glad we answered Dan's question
This makes sense because when I finally got around to putting my AC Schnitzer rims on, one of the tires hadn't sealed properly to the rim and was losing air. When I parked the car after driving it home from the tire shop, everything was fine with the TPMS (I had done the reset on the system after the new tires were installed). Four days later when I went to use the beast, it immediately alerted me about a tire pressure problem with my left rear tire. This was immediately upon starting the car -- I had not moved an inch.
It would not be possible for the system to alert me of the low (not flat) tire pressure in the left rear tire without being able to measure the actual pressure and compare it to my setting in iDrive.
It's a 2009 M6 Convertible, Black sapphire metallic exterior with Sepang Bronze leather interior. Quite unique color combo.
Only 17,000 miles, all options including steering wheel heater, soft close doors, heads up display, individual audio system, comfort access, heated seats, alarm system, wood trim this time, navigation, etc.
Found her for sale on a dealership in Georgia. I bought it two days ago.
I am flying to Atlanta on Monday to close the deal, then I am having her transported to my home via an enclosed container next week.
Expected transport time is 10 days from Georgia to Everett.
Cant wait to welcome Betsy IV to her new home.
First mod is SmartTop module convertible control. Then all LED lights.
Photos of my new beast coming soon. I cant wait to have her.
Betsy III is now officially listed at Auto Trader and Cars dot com for sale.
Evolve ECU Tune, Tubi Rumore exhaust, BBS RGR rims; Polk Audio Tweeters, 5500K Osram Cool Blue HID,Valentine 1 Radar Detector; Laser Interceptor Laser Jammer; All LED interior lights, LED footwell lights, LED trunk lights, Ultimate Cup Holders, 3rd brake light LED flasher, ash tray delete; LED license plate lights; RPI Ram Air Scoops + Block off plates; BMC Air Filters.......
I was reading up on this last night. My curiosity got the better of me. The older FTM system, (which I had on my 645), does mention measuring tire rotation, however when you dig deeper what it really did was send the pressure reading, which had +/- 5% accuracy, to the RDC or RDW module that was in those vehicles. The module calculated tire rotations per km and via a preset formula displayed a low (flat) tire condition to the CCC (iDrive display), when the calculated rotation speed differed from the last reset performed by the driver. The tire pressure sensors were/are actually made by Bosch and they did in fact read tire pressure not rotation itself. So the manual was giving us laymen's terms on its operation. There are two frequency bands (in the U.S.) that are used for FTM/TPM's. and the internal watch type battery is good for approximately 10 years.
The web is a dangerous place. But back to the original post by Dan, the actual tire pressure in lbs. is not displayed anywhere. It's still just an indicator of less pressure on each individual tire against the pressure measured from the previous reset and displays a warning The module also takes into consideration the outside temperature and speed the car travels. I couldn't find how often that algorithm updates during a drive, but I do know you can code the pressure change you want the indicator to alert you using nettodat. (the first screen you see when you read a module).
Way TMI, but thought this might make interesting reading. So I still like the Hella system and will install it one of these days. I have the TPM system on my 07. I think they switched in build month 9-06 thereabouts.
Porsche Gemballa Avalanche (4.3 litre), RSR 1600-RR - 1600 hp on race gas
Porsche Gemballa Gt600 - Carrera 4s compressor ( VF-Engineering ) 600 hp
Porsche Gemballa Cayenne Gt650-R. 650 hp
Ferrari 599 GTB Novitec Rosso SuperSport - 888 hp
Lamborghini Aventador LP-760 Mansory Edition - 754 hp
Aston Martin 1-77. V12 - 770 hp. No 57 out of 77
Bmw X3-F25 35i Xdrive M-Pack 380 hp - AC Schnitzer
Bmw M6-E63 Schnitzer 600 hp - Heavily modded
Bryan, my good friend.
I am doing ok I guess. As usual with ups and downs. Not good to be 54 years old.
Wife drives the X3 35i MPack and now she wants the Gemballa Gt550 for a more 'sporty look' when she goes out, not for business.
So I need a daily ( exotics are excluded ).
I placed few months back an order for the new M6 with G-Power. I cancelled it and I am back again. Now I have a firm order for the new M6, delivery January 2013.
It is deep sea blue with sand beige interior and most options.
We will see. If it plays tricks on me like the old M6, then M// is permanently terminated from my wish list.
I might try the new Porsche 991 then.
We will see.