Circuit Description

WARNING: This page is about a different car, the 2002 GMC Yukon XL, 2002 GMC Sierra, 2002 Chevrolet Suburban, and 2002 Chevrolet Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The Transmission Range (TR) switch is part of the Park/Neutral Position (PNP) and back-up lamp switch assembly, and is externally mounted on the transmission manual shaft. The TR switch is a multi-signal switch. The PCM supplies ignition voltage to the TR switch on 4 signal circuits ("A", "B", "C", and "P"). Each gearshift lever position grounds one or more of the switch circuits. In order to determine the gear range selected by the driver, the PCM compares the voltage combinations on the signal circuits to a look up table stored in the PCM memory. PCM detects the selected gear range by the state change of the switch input. See TRANSMISSION RANGE SWITCH LOGIC table under DESCRIPTION & OPERATION.

Switch input to the PCM is represented on the scan tool as HI and LOW. HI indicates an ignition voltage signal. LOW indicates a zero voltage signal. The 4 parameters represent transmission range switch signal "A", "B", "C" and Parity.

DTC P0706 will set if the PCM detects start-up in a Drive range or vehicle speed in the Park or Neutral range. DTC P0706 is a type "C" DTC.