Tire size correction?

I got done early at work today so I decided to bring my 2004 Cavalier in the shop and play around with (er, uh, I mean learn) our relatively new Tech-2. I was going to correct the tire size while I was in there (speedometer off by a few percent), but I couldn't go into 'Chassis', each time I got the same 'no communication' error. 'Powertrain' and 'Body' worked fine, I could see all data and command everthing on/off so I know the connection was good. Should the Cavalier have anything under 'Chassis'? If not, does anyone know how to correct the speedometer?

Thanks

The Vss is located in the drive train. I've never got my hands on a tech 2, but I know how to do it with HP tuners.. lol

PPM= Pulses Per Mile
Diameter= The Diameter of the Tire

PPM x (Old diameter/New diameter)= new PPM

Example:

24212 PPM x (25"/23")= 26392 PPM

go to speedo option it brings up "VSS Pulses Per Mile"

See if you can find it in the transmission setting somewhere since the VSS sensor is that. Not chassis...

I checked out the HP tuner website, I might have to get one of those, maybe I'll try to talk my boss into buying one for the shop first :biggrin:

In the Tech-2, the tire correction is in the 'Chassis', at least on trucks. I've seen it in there several times, but never wanted to risk playing around on a customer's vehicle. When I left today, tomorrow wasn't looking very busy... maybe I'll take another look.

And you've got a PM