Thats incorrect info, atleast in the case of the Dakota and most vehicles I have worked on (I am a fleet mechanic). It uses sensors inside the wheels to actually read the tire's pressure and send a message wirelessly to an onboard computer that interprets the signal and turns on a warning light if it senses one or more tires are low.

The more sophisticated systems actually can tell you which tire is low and what its actually pressure is is a display on the dash, either in the instrument cluster or the media screen if it has one. No way ABS could do this.

 

No I havn't but I spent about 30min on the highway with it and I figured if it wasn't working the light would come on. Maybe when I get a chance I'll try dropping one tire down and see if it pops on.

Last week we had some REALLY cold temps and the TPMS light would pop on when the truck was first started and then go out after 10min of driving and the tires warmed up so I know the system is working.

 

Some European cars use an indirect system, they work as Alfons described. According to wikipedia, Audi was the first to use indirect in the US.

 

Not saying the ABS system doesn't exsit. Just not correct info for our Dakotas.

 

Silly question you don't have the old rims/tires in the bed do ya?

 

I'm not sure how the TPMS is on the Dakotas, but my kia has two lights. One for the low pressure warning and one for a fault in the TPMS system, my fault light is on all winter since I didn't buy sensors for the winter setup, turns off after a day or so with the summer stuff installed.

Do our dakotas have two lights or just the one?

 

Just one light that I noticed when skimming the owners manual.

Tires are stacked in the garage.

 

Perhaps you'd be so kind as to point out exactly where this sensor is located on each wheel and how it will transmit that information to the computer? The ABS sensors are there and they do report the rotation of each wheel, but they DO NOT watch your tire pressure - for this, the sensor would need to be in the rim or tire.

 

I did some quick research and probably should have done that earlier, but I may or may not have been right depending on the year of the vehicle. Here's a link to a site that talks about Chrysler TPMS. Have a read and see what you think. I know that a lot of earlier vehicles used the ABS sensors for calculating comparative values to take a guess at whether you should check your tire pressure or not. If your truck has a built in wireless system and a sensor in the valve assembly area, then you may have a real TPMS or an indirect system.

 

Most manufacturers use this style of sensor
http://t1.gstatic.com/images?q=tbn:A...uow45jyl2zwp2Q
I don't see what the big argument is here..Its a sensor connected to the valve stem that wirelessly sends signals of PSI in the tire to a computer. The computer has set values, probably ranging from 32-35) and if PSI is not in this range it will trigger a warning light on the dashboard. Indirect systems won't be used in cars/trucks much longer. They may have been common when TPMS systems initially came out but now that all new vehicles must have this feature I believe manufacturers will use the direct systems.