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 TCC brake switch for proper adjustment. Check PCM calibration for current update. Check ABS operation. Inspect wiring for poor connections at PCM. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for moisture and corrosion. Check for chafed wires that could short to bare metal or other wiring. Check for broken wire inside insulation. If diagnosing for intermittent short or open condition, move wiring harness while observing scan tool for value changes.