You need to see a dealer. But I would NOT go back to the dealer who can't read what the correct tire inflation should be. If they can't even inflate tires to the correct pressure, why whould you expect they could diagnose and correct a computerized suspension system?

 

Wolfdogs – But I love the ride and that is another reason I bought the extended warranty – just in case this type of problem comes up and dealer just starts replacing things to see if that fixes it.

Vette 05 – thanks for the information on the battery. That is something I will check into.

HOXXOH - I really did not think tire pressure of 2 lbs. would cause this problem but was hoping for a simple fix. I still plan to pump them up to 30 lbs. just to take it out of the equation. I agree, why do they pick 158 MPH? Seems like a strange message to have and right or wrong, I translate that as a minor issue with something but I still want it corrected.

Cool Rod – I will let the dealer know about one possible cause and good to know that they could put a device in to record problem since I normally drive the car on weekends and the people that work on the car at the dealer will probably not be there when I have the message come up.

Thanks to all for giving me some advice on this. I never will go over 158 MPH anyway but who wants that message coming across as you drive. Hell, if I wanted that I would have bought a Mustang.

Old Buckeye

 

I looked at my service order and this is what it says was the correction for my problem:

"necessary to replace wires and terminals from right front actuator to suspension module per technical assistance".

Maybe that will help, if it's the same problem.

Cheers

 

But you never know. I offered it as a suggestion since his problem seemed to start after they decreased the tire pressure by 4PSI. I hope the programming isn't that sensitive since the actual TPMS is off by 2-4PSI especially if you live at higher altitude.

 

1/4 psi is big,in racing,especially F1.

 

now there's a statement you would not hear "back in the day"

 

I've been running mine at 27 in the rear since I bought it a few weeks ago and have had no problems.

 

not 1/4...LOL... but it does change things.............

Because of its thin tread structure, a slick racing tire's vertical compliance is softest at tread center where neither sidewall adds stiffness. This provides the largest and most flexible contact patch at a given load and pressure, thereby allowing the highest contact coefficient of friction. This differs with regular street legal high performance tires, where sidewall stiffness has the direct impact on the overall contact patch of the tire due to the inner belt design and support wedging on the sidewalls.

 

Just as a follow-up message on this problem - I pumped the tires up to 32 pounds and made sure the battery was fully charged and would still get the DIC message to Service Ride Control – Maximum Speed 158 MPH.

So I took it to the dealer and they said the message was saved and it indicated one shock needs replaced. I wonder just how definitive these messages are. Could it have been a loose wire to the shock and it throws out the same code? Just wondering.

I did notice that each time I drove the car, it took about 40 minutes of driving before the message would appear. Not sure what that really means.

I pick the car up tomorrow so we will see if I still get the same message. I have read on this forum that these shocks are so dependable but this one only lasted 10,500 miles. Hope the other three do not have the same issue since they are expensive. Thank goodness for the extended warranty.

Old Buckeye

 

what setting did you have s/ride on ?

 

Tour

 

I don't know where that 158 mph comes from.

I was running my ZR1 at the Vettes for Vets event at Talladega this spring, and I recorded a couple laps with my iPhone using my Innovate OT-2 connected to the OBD 2 port.

Here's a segment of the data that shows the car up at about 168 mph:




You can see that data is displayed for 3 different lines: the purple one is RPM; the sorta green colored one is Throttle Position; the orange one is the VSS (Vehicle Speed Sensor) speed.

Starting at the left of the graph you can see where I went WOT in 4th gear (the green line goes up and flattens out because I've got the accelerator flat on the floor). I ran up to close to the 6,500 redline in 4th and shifted to 5th and slammed the accelerator to the floor again, and the green line went flat again.

You can see a vertical line - that's at the max RPM I reached in 5th gear just before letting up on the accelerator pedal.

The purple line keeps climbing to 5860 RPM in 5th, which equates to about 168 mph.

HOWEVER, notice that the VSS (orange line) goes flat while the RPM and actual speed of the car continue to increase.

You can see on the graph that the max VSS readout is 158 mph.

For some reason the VSS speed is only indicating 158 mph while the car continues to accelerate faster than that.

Bottom line - VSS speed doesn't go above that weird 158 mph number, but it sure didn't keep the car from going faster than that!?!?

BTW, I didn't have any DIC messages, although sometimes after logging some data, when I disconnect the OT-2 from the OBD port, I'll have a message to "Service Ride Control", but it goes away after turning off the ignition and then starting the car.

Bob

 

Your tires aren't extremely sensitive. Air pressure is related to heat. When colder you need to add more air to increase pressure. When it gets warmer you may need to let a little air out.
The proper inflation is 30 pounds cold all the way around.

 

Pressure changes about 1 psi for every 10'F.

 

Zaino will fix it.

 

They are not covered on most extended warranties. I don't even think the factory covers them after 1 year since they are wear/tear items.

I had the F55 in my 08 and it is a great suspension. There is always that what if it fails though. My dealer said they are not covered, even under GMPP.

 

@BEZ06: that is very interesting. I'm in trucking, and I know that on our trucks the VSS can actually limit a lot of functions. If it looses pace with the truck, it can retard the unit and limit its maximum rpms. Interesting here that it looses pace and then allows the car to continue to accelerate.

Nevertheless, I found myself chuckling that our cars electronic nannies have a problem and slow the car to a "safe" 158mph. It's like two engineers got together and said "hey, if this component goes out, how slow should they be driving? I guess 158 mph sounds about right."

Good news is we can have a service issue and still pass a BMW or Benz on the autobahn.

 

YOu don't say where you live, OP, so I'll just assume it's a place with only one dealer close to you. But the above is worth reading again by Fort Morgan Al, as are the posts 19 and 20.

 

Never let anyone adjust tire pressure down when hot this results in low tire pressure. Ever time they change the oil in my daugthers Corvette it would start setting off low tire pressure warnings in the mornings cold. Dear old dad had to give them a lesson in person involved the Service manager no more problems. I mean are they stupid or what.
z51vett
Ps they now leave all my cars tire pressure alone unless i tell them to add air.

 

My last post on this subject - After one new shock and one sensor, no more limitation of 158 MPH. Ozzy12 - I could not agree more with your statement. Who decides that 158 MPH is safe when DIC is indicating to Service Ride Control and nothing mentioned in book about this message. I wonder what goes wrong and how severe when you get the 80 MPH limitation? Hope I never find out!