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Home >> Cadillac >> 1994 >> DeVille V8-4.9L VIN B >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Transmission Position Sensor/Switch >> Description and Operation
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Transmission Position Sensor/Switch: Description and Operation

Transaxle Range Switch:






DESCRIPTION
The Transmission Range (TR) Switch (formerly called a PRNDL, P/N or NSBU switch) is mounted externally on the transaxle at the manual shaft. The TR switch provides information to the Powertrain Control Module (PCM) about the selected gear range of the transaxle. The TR switch identifies whether the transaxle is in PARK/NEUTRAL (P/N) or any of the five drive ranges (R/D4/D3/D2/D1). The TR switch is also used to illuminate the backup lamps when the transaxle is in REVERSE (R).

The PCM uses TR switch status for idle speed control. A faulty TR switch should set a Diagnostic Trouble Code.
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