NoahGW

I have a 2002 C5 that I was driving normally today and the messages "Service ABS, Service active handling, service traction control" came on. Pulled codes, no codes. Just said this:

Car has c6 wheels and tires and no TPMS. 50,000 miles

NoahGW

Well, never mind, looks like another code came up.

c1214

tblu92

On a C5 when you change tire diameters you must correct the diameter in your tune in order to keep the Speedo correct and to keep the traction control/ABS? active handing working 100%-----Most C5's have a 26" tall tire programmed into the ECM A small variance would not make much of a difference but the further OFF you are from stock --it affects all the systems I mentioned--However If making a rear diff gear ratio change on a C5 you NO NOT have to correct the speedo -as the speedo sensor is on the output shaft of the diff ( unlike an F body) But you should still do a "shift point correction" if your car is an automatic
Other than having a non stock rear tire diameter On older cars the most commom culprit for all your codes is a fouled or broken "wheel speed sensor"
The wheel speed sensors are used by the ABS system to control wheels skidding on a hard stop---By the traction control to prevent wheels from spinning on a hard launch
and by the active handling to keep the wheel speeds equal from left to right on hard cornering------So if you are getting all 3 warnings--chances are it's related to the wheel speed sensors----------