Transaxle Range (TR) Switch

The TR switch (formerly called a PRNDL, P/N or NSBU switch) is mounted externally on transaxle at manual shaft. The TR switch provides information to PCM about selected gear range of transaxle. The TR switch identifies whether transaxle is in PARK/NEUTRAL (P/N) or any of five drive ranges (RID4/D3/D2/D1). The TR switch is also used to illuminate backup lamps when transaxle is in REVERSE (R).

The PCM uses TR switch status for idle speed control, and also as a backup to transaxle pressure switch. If transaxle pressure switch is faulty, PCM will select a transaxle gear based on TR switch status. A faulty TR switch should set a PCM Trouble Code.