Diagnostic Aids
WARNING: This page does not describe the selected car, but rather 36 other vehicles, including the 2002 Pontiac Firebird, 2002 Oldsmobile Bravada, 2002 GMC Yukon XL, 2002 GMC Yukon, and 2002 GMC Sonoma. However, it is still accessible from the selected car via links, so may be relevant.
Check wiring for poor connections at PCM connector and transmission. Check for bent, backed out or broken terminals, or misaligned connectors. Inspect for damaged VSS or for damaged output speed sensor rotor teeth. Check for moisture and corrosion. Ensure VSS is aligned correctly and secured to transmission case properly. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.