GM Service Manual Online
For 1990-2009 cars only

Odometer

The odometer display is supplied by a square wave vehicle speed signal from the EBTCM and has a 6-digit display with 1 mile resolution. When the limit is exceeded (999,999 km+1 km or 599,999 miles+1 mile), the odometer is reset to 0 km or 0 miles and continues counting. The odometer tolerance is 0.5 percent.