I have an 07 MN6-Anybody have an issues with there's not responding-I just had the button replaced (Under warranty) and its doing the same thing again-won't go into "comp driving mode" or T/C won't turn off etc. Thanks

 

That's a bummer, guess its back to the dealer.

 

Have you had any indications of your tire pressure sensors not working properly or TPMS problems("Service Tire Monitor" msg, or low pressure or "xx" pressure readings)? Maybe your sensors aren't properly registered with the TPMS.

What you describe is sort of a problem you get when you have sensor or TPMS problems. When no sensors are detected you generally are unable to go into Comp mode or disable AH, although you should still be able to turn off TC.

Bob

 

Took the words out of my mouth Bob. You are the KING of pressure sensors!

You describe precisely what happens in my car, only sometimes, when I'm driving my drag radials. Had them on for 2 days and 200+ miles before I got the sensor message last time. Odd, no rhryme or reason to when they don't register, sometimes 60 miles, sometimes they never throw an error.

 

Yes! I put 17x9 ZO6 Repro Wheels on the rears w/P275 MT ET Street Drag Radials. Since then I get xxx pressure read for the rear tires. Is that what's causing the problem?? any way to correct it other than mounting the 19x10s back on w/the RunFlats??

 

That's it. Park next to your regular tires over night and might be fine for the next day, it takes my car a long time to notice they are gone.

By the way head out to Countyline today. Every Sunday you can make 50 runs if you like, there's hardly anyone there. Best way to practice bar none - and the sunshine on the track makes it nice and sticky.

 

i dont know if this is true with the stick or with any other autos, but i tried that with mine, with the tps sensors in the canister i could drive for a month or so with out every coming close to it because the sensors were a sleep in the canister more than 70 ft away from the car. but the first time i jumped on the car and got good traction, and it had to be with good traction 1.5s then i would get limp mode

 

That's what's causing the problem!

First of all, most all of our drag racing experts here on the forum strongly advocate running on the drag strip with full Active Handling on. You can turn off Traction Control, but leave AH on.

I take it you don't have sensors in your DR's. One solution would be to put sensors in them. The only problem you'd have then is if you run low pressures (less than 24psi) in them, in which case the TPMS will detect low pressure and put up a DIC message, and probably put you in the limp mode. If you run 24psi or greater in your DR's you won't have any problems at all if you run sensors.

As Joe_G says, if your TPMS still has the sensors in your street wheels registered in its memory and you have your wheels with sensors in your garage, your TPMS will pick them up when you park in the garage. The DIC will display the pressures on the wheels in the garage and you probably won't have any indications of no sensors unless you drive for more than one hour straight (without shutting off the engine). As Joe_G says, sometimes you can clear the indications and drive normally, sometimes you can't and you get the limp mode.

As Dennis50NJ says, some owners have built a pressurized cannister they can put sensors in and store it in the storage cubby hole in the hatch and they have no problems.

I like the idea of running sensors in my wheels that are mounted on the car - I like the ability to see what my pressures are or to be alerted if I lose pressure. If you have runflats, you really must run with sensors.

Bob

 

that's what i do i keep the drags as my permanent tires but my fronts are run flats with the sensors i only have the back two in the canister

 

One slight clarification to Bez06's post, in my 05 I NEVER get limp mode when it notes no pressure sensors. I just can't select comp mode - TC on or off only.

And I ABSOLUTELY recommend running active handling/comp mode if you can get it - if you hit a slick spot down track shifting it might save your a$$.

And it really doesn't follow rhyme or reason if it kicks it or not. I drove for 2 days, for hours on end in stop and go traffic one day on my DR's, no notice. My drive to the track is 1:15 minutes, sometimes I get it one hour in, sometimes not at all, last time, when I was 15 minutes from home. It's odd that I can't figure out the pattern.

 

you accelerated hard somewhere on the way

 

Heck yes I did! Drove up to track, raced, drove home, got the check tire pressure sensors 15 minutes from home on the way back.

I've never had limp mode! Odd. But I'm glad!

 

I've gotten the limp mode twice - at least I think it's what people call the limp mode.

The first time was when I picked up a nail and the pressure went down. I got a message to "Limit Speed to 55", but I found the car didn't do anything to keep me from going faster than that - it was just an alert message.

The second time was when I swapped to another set of wheels and purposely didn't register the new sensors - I wanted to check out how the system worked.

First of all I put 2 different wheels on the rear - like you'd do with DR's. Almost immediately when I left my driveway I got a "Service Tire Monitor" message followed by messages about "LR xx psi" and "RR xx psi". I think the system picked up transmissions from the 2 front sensors so the TPMS knew that at least 2 sensors were working and that if the others weren't checking in that something must be wrong with them. I could turn off TC, but I couldn't turn off AH or go into Comp mode.

I put 4 new wheels on without registering the sensors and initially nothing at all happened. The DIC displayed some pressures, but they were the pressures in the old set of wheels/tires that was still in the garage. I drove around for about 15 minutes and had no problem going into Comp or turning off AH.

It's kind of hard to figure out exactly what they're talking about, but the owner's manual says that after approximately one hour without sensors you'll get the "Service Tire Monitor" message.

My wife wanted to go shopping in Orlando, about 65 miles away, so I had the new wheels on but did not register the sensors (same as no sensors at all). At first there was no difference from driving with sensors. When I got to about 1 hour from home I was expecting the message in the DIC, but it didn't pop up until about 75 minutes into the drive. I had been running in Comp Mode, but when I got the message it automatically turned full AH back on and I couldn't go into Comp or turn off AH with the button. I could go as fast as I wanted - the "limp mode" didn't do anything to slow the car down.

When we got to the shopping center my wife went in and I played around a bit. After shutting the car down and restarting everything was back to normal - I was able to turn of AH and go into Comp.

So....I think if you have sensors in a couple of tires and no sensors in others, you'll probably get messages sooner than if you don't have any sensors at all, and although you can reset the messages I don't think you'll be able to turn off AH or go into Comp.

If you have no sensors at all, it appears that you can drive for about 1 hour straight (without shutting down) before you get messages. When you do get messages you won't be able to turn off AH, and if it was off it will automatically come back on. However, just shut the car down and restart and clear messages and you can turn off AH.

Another issue is that it appears that cars that were made at different times may have different tolerances for running with no sensors - you'll just have to try your car to find out.

Also, although my experience is that the "limp mode" is just a message, like Dennis says, if you are accellerating hard or if you are cornering hard on a road course, there may be some actual stuff the car does to slow you down. If you get the limp mode message the car thinks you either have low tire pressure or problems with the TPMS that won't let it tell you if you have low pressure. If you drive aggressively and pull more than a certain amount of G's the PCM may actually pull timing or shut off fuel to slow you down - and I think that's what Dennis has experienced.

That's about all I can tell you from my experience.

Bob

 

Thanks for all the 411 Bro

 

I was looking at something in HP Tuners yesterday and noticed that the car has 2 speed limiters built into it - perhaps the 2nd speed limiter is the "flat tire" limiter. That limiter was set to 80 mph in my factory tune.

 

Thanks Bro -sent u a PM