Test H: Range Selector Display Inaccurate Or Displays Incorrect Range (4L60E): Description
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2001 GMC Savana Special, 2001 GMC Savana Camper Special, 2001 GMC Savana, 2001 Chevrolet RV Cutaway, and 2001 Chevrolet Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
Transmission Range (TR) switch is part of Park/Neutral Position (PNP) and back-up light switch assembly, which is externally mounted on transmission manual shaft. TR switch contains 4 internal switches that indicate gearshift lever position. Powertrain Control Module (PCM) supplies ignition voltage to each switch circuit. As gearshift lever is moved, the state of each switch may change, causing circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. PCM detects selected gear range by deciphering the combination of voltage signals. PCM compares actual voltage combination of switch signals to a TR switch combination chart stored in control module memory.