DTC P0706: Transmission Range Switch: Description

WARNING: This page is about a different car, the 2001 GMC Savana, 2001 Chevrolet RV Cutaway, 2001 Chevrolet Cutaway, and 2001 Chevrolet Chevy Express. 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 and back-up light switch assembly and is externally mounted on transmission manual shaft. TR switch is a multi-signal switch. PCM supplies ignition voltage to TR switch on four signal circuits (A, B, C, and P). Each gear selector lever position grounds one or more switch circuits. To determine gear range selected by driver, PCM compares voltage combinations on signal circuits to a look up table stored in PCM memory. PCM detects selected gear range by state change of switch input. See Fig 1. Switch input to PCM is represented on scan tool as hi and low. Hi indicates an ignition voltage signal. Low indicates a zero voltage signal. Four parameters represent transmission range switch signal A, B, C and Parity. DTC sets when PCM detects start-up in a drive range or vehicle speed in Park or Neutral range.

Fig 1: Transmission Range Switch Logic

Courtesy of GENERAL MOTORS CORP.