thnkfast

I went to the track yesterday and found out the hard way that my car ('05 Z51) would not allow me to disable active handling with a tire pressure sensor broken. I just bought 4 stock '08 wheels for track days and they have no TPM's in them. Do I have put TPM's in these wheels or can you disable the TPMS? The dealer told me they can't do it because of Federal laws. I would appreciate any help.......thanks,

Todd

thnkfast

anyone?????

ghoffman

Why not just buy the TPS sensors and use them? I love having them on my Hoosiers.

thnkfast

I guess that's what I'll do, just thought there may be another option.

davidfarmer

you can shut the system completely down before going on track.....press the ah/tc button for about 10 seconds. Of course you have NO help other than ABS at that point, but that is the way I drive

Aaron Pfadt

David,

The problem with that is that without the sensors, you can not turn the system off. It goes into a fault mode and will not allow you to do anything with the Active Handling button.

I have avoided the problem thus far, but I'm worried it will bite me at a bad time (on grid for example). As I learned from another Corvette track day enthusiast, keep the stock tires close by and park by them. Then the car will register the pressures. It's kind of PITA carrying around tires you are not going to use.

I hope to find a real solution soon.

-Aaron

Bravada

I could be wrong but I thought I read somewhere on the forum, maybe in tech section that someone took a PVC tube, put some previously learned sensors in, sealed it, put a tire valve on it and set it to correct psi and just put it in one of the rear cubbyholes. I'd search it for you but search and me don't get along.

gkmccready

One alternative I've heard about is to learn a set of sensor that you will never, ever be near again... a single failure freaks the ECU out, but if all four sensors go away the ECU will apparently just quit bugging you about them after you drive "enough".

I had a flakey sensor at a track day and it was *dangerous* to be on track. I run with everything off, but as soon as that sensor intermittently cut in and out the car would pitch a fit... it slammed on the brakes on entry to T10 at Thunderhill and the only thing that saved me from having a passenger where the backseat should be was that I had opened up enough of a gap after the pass.

So, yeah, the sensors are great when they work, but their failure mode is scary. That said, I still have them in both sets of wheels and use a programmer to learn them as required...

evo1313

I too have had some problems with the TPMS.

I was at the track and my car would not recognize the sensors or any pressure (even with the reset tool) so you could not turn off the active handling (this really sux).

I removed the ABS fuse so I could run with some speed and found out the hard way that without the ABS fuse, there is too much rear brake bias and luckily only flat spotted a set of tires to avoid the wall at the end of the straight.

The wierd part of this is the car sat for 2 weeks after and when I went to get the new tires put on, it recognized the sensors and I was able to turn the active handling off ??????? I dont get it but it did screw up a whole day at the track and $1500 worth of tires.

My plan is to get a brake bias put on so that if the sensors act up again I can still pull the fuse and run without worrying that the car is going to swap ends with me.

I dont know if this helps any but it might shed a little more light on what we are all up against.

BEZ06

Sorta!

You're right that once you program the ID#s of a set of sensors into the TPMS, it will remain in there and display the last known pressures of those tires - at least until you someday unhook the battery, then the TPMS will lose those last known pressures and display "xx psi" in the DIC.

I don't believe the TPMS will ever quit bugging you.

However, if you have no sensors at all, it takes "approximately one hour" (read about it in the owner's manual) before the DIC will give you an "xx psi" in all 4 wheels and "Service Tire Monitor" message, probably followed by a "Limit Speed to 55" message. If you had AH off or in Comp mode it will automatically come back full on, and if you drive very aggressively it will pull power on you.

This requires about one hour of steady driving without shutting the car down. When you shut down you should be able to reset and clear all messages and have about another hour of no problems.

Like gkmccready, I had a sensor that apparently didn't get registered properly when I swapped to my track wheels/tires/sensors. In the middle of a session the AH came back on (I was in Comp) and started grabbing brakes, and a couple of corners where I was trying to rotate the car, the engine would just die when I tried to accelerate out of the corner. I had to come in and reprogram the sensors, then had no more problems.

What happens is that the car can't imagine that you're running with no sensors, and it really can't imagine that all will fail at the same time. It's programmed to decide that after about an hour without getting any transmissions from any of the 4 sensors, the problem must be with the TPMS computer in the car (and you get the Service Tire Monitor message), and not the sensors.

So....if your track sessions aren't longer than approximately one hour, you shouldn't have any problems running with no sensors and you should be able to go into Comp mode or turn AH all the way off. If you're doing endurance racing with more than one hour out on the track before you come in and shut the car down, restart, and clear all messages, you'll probably have your AH coming back on during the session.

Butt.....YMMV! Cars built at different times and different model years seem to have different tolerances for running with no sensors. You'll just have to try your car to find out how it's going to react.

Bob

ghoffman

Again, why fight it, just use the sensors!

BEZ06

wholeheartedly!!

Just trying to explain what I think is going on.


Todd, they can't do it not because of Federal law, they can't do it because it's impossible to do (unless you can crack into the GM proprietary software coding in the RCDLR/TPMS - and we've been trying that with the Nav for almost 5 years with no success!).

The C5 came with runflats, sensors, and a TPMS in the car to receive the transmissions from the sensors. When they came out with the C5 Z06, it did NOT have runflats or sensors - and the TPMS was not activated in the car.

If later on you wanted to put on runflats and sensors (and if you're driving on runflats you really must have sensors), the dealer could use a Tech 2 to activate the TPMS. Likewise, they could deactivate it if you didn't want it.

Sometime around when the C6 was being introduced Congress tasked the NHTSA and DOT to come up with guidelines to keep soccer moms from running their Firestones at too low a pressure in their Explorers and killing themselves. A law was passed that required all 4-wheeled vehicles less than 10,000 pounds to have sensors and a TPMS by Sept 2007 - the start of the 2008 model year. Also, the manufacturers had to start back in about 2005 implementing the law on an increasing percentage of their vehicles so that by Sept 2007 100% complied. The C6 got the sensors and TPMS required by law to help GM meet the percentage required that year.

So.....the dealer is sort of correct in that they can't do it by Federal law, but even if they wanted to they couldn't. It CANNOT be deactivated in a C6 or any 2008 or newer car - there's no way to do it.

Well....I have heard of at least one outfit that about a year ago was going to try to hire a software guru to rewrite the code and do away with the system on track cars - but I haven't seen any indiation that they've been successful yet.

I like sensors in my track tires. They're not going to protect you from a blowout, but if you've got a slow leak the DIC message might keep you out of the Armco!

Bob

85scott

Because for a lot of drivers, it's just a useless expense & PITA.


BEZ06 Gotta say you seem to really know your stuff. But after hearing the horror stories from track guys, I'd still like to get rid of it when I replace tires. Unfortunately, you say not even pulling fuses will kill the beast.

Yet Computers Nannies going haywire with random braking & power reductions, could happen to anyone at any time. And even if TPMS is maintained properly, since there's no guarantee sensors & computers couldn't fail anyway.

So it bothers me knowing the only thing between IT taking control of my car is another high tech gadget I don't even need.

Big Gov should have never allowed such an intrusive device on cars.
Not without also giving people a cost free method to disable ALL of it.

Instead they treat every American like they are hopelessly stupid!
And lawyers & DC make safety into another pointless race to protect the bottom.

JerryTX

4 year old thread alert!!