Diagnostic Aids

WARNING: This page does not describe the selected car, but rather 14 other vehicles, including the 1998 GMC Savana Special, 1998 GMC Savana Camper Special, 1998 GMC Savana, 1998 Chevrolet RV Cutaway, and 1998 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.

Inspect wiring for poor connections at VCM and at transmission 20-pin connector. Check for bent, backed out, deformed or damaged terminals. Check for weak terminal tension. Check for chafed wire 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 change. Check engine and transmission harness for open condition. First diagnose and clear any engine and TP sensor DTCs that are present, then inspect for any transmission DTCs that may have reset. TFT sensor temperature should rise steadily and then stabilize. Test TFT sensor at various temperatures to evaluate for skewed sensor. See TEMPERATURE-TO-RESISTANCE VALUES table. A skewed sensor may cause firm shifts or TCC complaints.