97coupechuck

Had some work done and had a new tune on LS2 and it runs fine but can't turn off Active Handling. It will turn off Traction control but that's all!! Have a local HPDE here in texas next weekend and don't want to drive in company with it on. Any ideas where to look?

wtknght1

Most of the C6s just have to hold down the TC button for 6-8 seconds and everything should turn off. It takes a while...

WNeal

Did you by chance disconnect the battery, even if for a second during this maintenance work.

If so, you will have to drive the car on the street for a minimum of 30 minutes (30 minutes of MOVING time)

I have gone through this more than once and that is what it was. We installed an emergency off switch and had to disconnect the battery to do this and that is when the problem started.

If you did disconnect the battery, give it a try

97coupechuck

thanks for tips, yes we did disconnect battery and drove for about 25 miles in city traffic (more than 30 minutes) and still no luck. Maybe I'll try it agin and put more miles on it this time. Jeez, I remember when I tore into 97 C5 way back and ran into these probs as I started working on it. Now I've been real conservative on touching this LS2 but after awhile I had to get more HP and here we go!
Still looking for clues..........................

BEZ06

I bet you swapped to track tires/wheels with no sensors!!!

Have you gotten a "Service Tire Monitor" message? That would be a dead give away that your TPMS computer in the car isn't receiving any signals from any sensors, and in that case it won't let you go into Comp Mode or turn AH off completely.

If you do have sensors in your track wheels, they probably just haven't been registered properly.

Bob

WNeal

City driving with stop and go might not do it.
the car has to be moving for 30 minutes

Could be TPM also as was stated above.
That usually clears up though immediately if you start the car, turn it off and then start it again. I have to go through that routine for every session I do. Good thing it is a track only car.

97coupechuck

Ya mon, I was thinking about that driving home tonight from the shop and I think you might have something there. I can't remember ever trying to turn off AH with the TPS's not set. I have not set the TPS's since I took off slicks and put streets on a few weeks ago.
Just got my POS TPS setter and as usual it's got a mind of it's own and will not go thru a full cycle of doing the monitors. So I'll be getting that done tonight or the POS TPS setter might be taking a ride to the garbage heap! Thanks for the tips guys, Ill let you know if I can work it out.

BEZ06

In your original post you say:

Is this an LS2 in a '97 C5, or this a C6???

If this is a C6 we might be able to help you out, but if it's an LS2 in a C5 you may have to figure this one out.

If it's a C6, the TPMS is part of the RCDLR module. Without sensors you can turn off TC, but without sensors you will not be able to go into Comp or turn AH all the way off.

When you unhook the battery the TPMS will drop the last known pressures out of memory, but it will retain the sensor ID#s so you won't need to do a sensor relearn procedure (unless you have a different set of sensors in your wheels from the ones that were originally logged into the TPMS memory - it can only hold 4 sensor ID#s).

When the car sits still for more than 15 minutes the sensors go into a sleep mode and only transmit once per hour. When you start driving faster than about 20 mph the sensors wake up and start transmitting once per minute. It shouldn't take more than a couple minutes of driving at more than 20 mph to get the current pressures to display in your DIC, which will give you control of your AH and allow you to go into Comp or turn AH completely off.

If this is a C6 and you have sensors in your wheels, I think you just have to register the sensors properly with TPMS reset tool.

If you don't have sensors in your track wheels you may be able to get away with logging your street wheels into the TPMS. If you don't run any track sessions longer than approximately one hour you may be okay. Don't unhook the battery or you'll be back in your current situation. Actually, if your street tires with sensors are in the paddock area your TPMS should pick them up between track session if you can park within about 30 feet of them - but without the wheels rotating the sensors will only be transmitting once per hour.


If this is an LS2 in a C5, I don't know what to tell you. If it's a '97 C5 it uses the early C5 sensors. I know the later C5 Z06 didn't have sensors, so the TPMS was deactivated. You can use a Tech 2 to turn the TPMS on/off in the later model year C5, but I don't know about the earlier ones. You cannot turn off the TPMS in the C6.

Good luck!!

Bob

BEZ06

Ahhhh.....I saw in your post in the other section that you do have a C6.

If you have a tool then it should only take about a minute to program your sensors. I don't know what tool you have, but they all work essentially the same. You just have to put the car into the learn mode, then trigger each sensor in the order LF, RF, RR, LR, then turn off the ignition and you're done. Make sure you get a honk of the horn at each wheel (double honk at the last one) or the TPMS did not receive the data transmission and did not log the sensor ID# into memory.

if you're having trouble getting the tool to trigger a sensor, make sure you put the antenna of the tool on the rubber sidewall of the tire right next to the valve stem - don't try to transmit through the metal of the wheel.

No matter what tool you're using, you'll put the car into the learn mode and use the tool just like in the video below.

Good luck!!

Bob

97coupechuck

BEZ06 you are dead on, GREAT INFO, I was able to get my TPMS tool to set three of the 4 wheels (?) and turned car on and was able to to get into comp mode and then hold for couple seconds longer and AH turned off! So I guess tomorrow I'll have to drive car a bit and try again to get all 4 wheels set otherwise I'll get another TPMS tool. another great reason for this forum to exist, I sure am thankful for everybody, one more lesson learned on C7 corvettes.

fatbillybob

Wow! this is the only way to solve this with a tool? Is there no way to turn TPMS off at the car ecu? How do you guys run street wheels and track wheels at different low sub 30psi? I wish gm would sell us a race version of these cars, no interior, no onstar, no tpms etc...

BEZ06

You can't turn the TPMS off on a C6.

There's a federal law that requires ALL 4-wheeled vehicles less than 10,000 lbs built since Sept '07 (2008 model year) to have tire pressure sensors and a TPMS. So....if it's built for the street it must have sensors.

The law actually required the manufacturers to phase in compliance so 100% of cars would have them by Sept '07, but when the C6 came out in the 2005 model year it was easy to make it with the system so that GM could comply with the 25% (or whatever it was at that time) requirement.

The TPMS is designed to protect you if a tire loses pressure. With the runflats you don't get any handling feedback if you lose pressure while going straight down the highway, so the TPMS won't let you turn it off or go into Comp mode if you have a flat, a sensor problem, or no sensors at all.

If you have sensors in a C6, the TPMS won't give you problems until the pressure in a tire goes below 24 psi, at which time it will automatically turn AH back on if you had it off or were in Comp mode. This is mostly a problem for drag racers who run low pressures in DRs, but some road racers run very low pressures.

I think Phoenix was working on a way to do away with the TPMS on a race car, but I don't know if they were able to do that.

The TPMS is part of the RCDLR module, and it interfaces with the BCM and PCM, and maybe a bunch of other stuff - so it won't be an easy task to get rid of it in a car you want to drive on the street or run in a class that requires the car to be pretty much stock (i.e., stock PCM).

I have seen some race prepped C6s that have had all the OE computers ripped out, including the PCM (replaced with an MSD or other aftermarket PCM/ECU). This would get rid of the TPMS and also gets rid of the requirement to have a fob in the cockpit to start the car.

Butt.....if you've got a pretty much stock C6, you can't turn off the TPMS in a C6.

Bob

fatbillybob

Thanks Bob! I wonder what guys do who run low cold starting pressures and then low hot pressures. I wonder what LS3 T1 racers are doing? I guess you can at least program with aftermarket tools the RCDLR to accept a low tire pressure? I think these ECU's are all linked to the main by CAN line. I wonder if there is a way to sever the connection and still have the main ecu function properly? Today we have all kinds of crap talking to the main ECU like alarm ECU's for example.

WNeal

I have an 06 that I run without TPM.
When I turn the car on, I get the DIC warning about the TPM. I then turn the car off, turn it back on and everything is fine after that.
I can turn everything off and don't have any issues.

I usually start cold pressures around 25

BEZ06

I assume you have a display of tire pressures in your DIC.

If you don't have sensors in the wheels that are mounted on your car, the pressures displayed in the DIC will be the last known pressures of the sensors that are registered with the TPMS. If those wheels are in your garage or pit area the sensors will transmit (but only once per hour) the pressure in the tires that are not mounted on the car. If you park within about 30 feet of those tires the TPMS will pick up transmissions from those tires so you'll be able to turn off AH or go into Comp.

If you disconnect your battery the TPMS will lose those last known pressures and display "xx psi" and "Service Tire Monitor" and you will not be able to turn off AH (the exact problem 97coupechuck had).

In your situation, where you don't have sensors but have old pressures displayed in the DIC, when you start driving the TPMS is expecting to get signals from the sensors within a couple minutes of driving.

If you have, say, 3 good sensors that send out a signal to the TPMS and one bad sensor, the TPMS knows right away that it's not receiving a signal from one sensor and will not let you turn off AH.

However, if you have no sensors at all, the TPMS is waiting for signals from the sensors and will keep listening for "approximately one hour" (according to the owner's manual). If the TPMS doesn't get any sensor signals at all for about an hour, you'll get the "Service Tire Monitor" message (meaning that the car thinks the problem is with the TPMS because it can't imagine that all 4 sensors went bad at the same time). At that time, if you're in the middle of a track session with the AH off, it will automatically come back on.

That "approximately one hour" is without turning off the ignition - you need to run an hour without shutting down the car to get that problem. If you do get the message and can't turn off AH, shut down, restart, clear any messages, and you should be good to go for another hour.

Bottom line if you're running with no sensors:

1. Don't disconnect the battery or you'll lose the last known pressures and won't be able to turn off AH or go into Comp.

2. If you're running long sessions (greater than one hour) your AH will probably pop back on after approximately one hour on the track.

BTW, you don't want to run on the track without any pressures displayed in the DIC. At Daytona earlier this month I ran my street tires in the wet the first day. When I switched to my Hoosiers I had a hard time triggering one of the sensors. They were staging for my session so I just went out with no sensors registered. On startup I immediately had a "Service Tire Monitor" message and all pressures read "xx psi". I figured I'd just run the session with AH full on (I usually run in Comp) - BAD IDEA!!!!

The DIC displayed "Active Handling" most all the way around the banking and in the infield turns. At speed on the banking the car was jerking and twitching around as the AH put on individual brakes (I found out later that it was mostly the RF). Coming out of a turn when trying to accelerate the engine would just die (like hitting the rev limiter) until I got the steering unwould and the "Active Handling" message disappeared from the DIC. The PCM pulls timing and I think actually reduces fuel if necessary if you try to accelerate while "Active Handling" is displayed on the DIC.

After a few laps I got ABS activating when it shouldn't have, then the brake pedal went to the floor when braking for a turn in the infield.

I limped back to the pits and found the RF pads run down and the rotor gouged. I think the AH was putting on that brake most of the time I was trying to run around the banking at 150 and it boiled the fluid. The left side and rear were fine.

I put on new rotors and pads both sides up front and did a bleed/flush of the system. I used my TPMS tool to register my street tires, which were stacked up in the paddock area, so the DIC displayed the pressures of those tires that were not on the car. The last couple of sessions I had no problems while running in Comp mode, but of course I wouldn't have gotten any alerts on the DIC if a tire started losing pressure.

Hope that long post might help to explain the TPMS a little better!

Bob

Jason

You can thank the moron Explorer drivers that had low tire pressure, had a blow out, then flipped when they panicked and slammed on the brakes.

BEZ06

And thanks also to "Big Brother" who knows what's best for us and passes a law to protect us from ourselves when we're too stupid to check our tire pressures every once in a while!!

Actually the sensors are very important when running runflats - you just don't get any handling feedback if a tire loses pressure while driving down the interstate. Without sensors you'd never know a tire went flat until you took the off-ramp in a spirited manner and ended up in the guard rail when a sideload built up.

Butt.....Corvettes have had sensors for a long time because they were a good idea, not because they were required. The C5 Z06 did not come with runflats, and the TPMS was not activated in them. If you put on runflats you could use a Tech 2 to turn on the TPMS, or you could turn it off on other models of the C5. Unfortunately the C6 can't be turned off.

Too bad congress couldn't have just left it as a good idea instead of making it mandatory.

Bob

fatbillybob

Remember when O2 sims were all the rage? We need to escalate the electronic war and find ways to deal with CAN feedback to main ECU's in a general way. Our future is not bright. We got E-diff, alarm ecu's, window ecu's, traction control, abs, drive by wire throttle etc. all causing real problems for racers. The next generation of babysitters will be because of the toyota sudden acceleration problem. I bet next we get FED mandated throttle cutout when brakes are applied. How will we left foot brake and modulate the throttle then? Porsche did that with some models and everyone had a cow about it. I've driven one of those cars they suck! When cars electronically apply the brake if you are closer than 1 car length/10mph what do you think that will do for your racing?