Theory Of Operation

The Transfer Case Range Position Sensor (RPS) is a serviceable component located on the top center of the Transfer Case next to the vent tube. There are two circuits between the sensor and the (DTCM) Drivetrain Control Module:

• Signal
• Sensor Ground

The RPS is a five-position, resistive type sensor. The sensor contains a plunger that contacts the sector plate inside the Transfer Case which has four discrete positions. The plunger moves in and out of the sensor body as the Transfer Case is shifted. As the plunger is depressed, the resistance value changes.

The sensor ground is used as a low voltage reference. The signal circuit feeds an analog input to the Drivetrain Control Module (DTCM) using a pull-up resistor to 5 volts. The resulting voltage value for each position is read by the DTCM to determine the Transfer Case range position. The voltage is also used by the DTCM software for diagnostic purposes.