C039E Buick Code - Range Actuator Position Sensor Direction Signal Circuit

The Transfer Case Control Module receives input from the range actuator position sensor and the transfer case range position sensor. Both sensors send this information as voltage signals which are converted to degrees and rotational direction by the Transfer Case Control Module software. If the two sensors disagree by greater than a predetermined amount the Diagnostic Trouble Code (DTC) will be set.
The range actuator position sensor receives an 8-volt reference signal from the Transfer Case Control Module. In return, the range actuator position sensor sends the Transfer Case Control Module a variable pulse width modulated signal indicating the position of the transfer case and a range actuator position direction signal. The range actuator position sensor, inside the A16 transfer case motor, also known as the transfer case range actuator, works in conjunction with the range position sensor to confirm the transfer case position. The range actuator position sensor is more sensitive than the transfer case range position sensor and is able to indicate to the Transfer Case Control Module the exact position of the transfer case between range changes. It is also able to show how much clutch activation is being commanded at any time.
The transfer case range position sensor, also known as the transfer case two/four-wheel drive actuator position sensor, receives a 5-volt reference signal from the Transfer Case Control Module and sends back a continuously variable pulse width modulated signal to the Transfer Case Control Module. This continuously variable signal indicates the position of the transfer case actuator.
The range actuator position sensor is more sensitive than the transfer case range position sensor but needs to reference the transfer case range position sensor value at ignition ON and mode changes. The transfer case range position sensor is an absolute sensor. The Transfer Case Control Module synchronizes the range actuator position sensor with the transfer case range position sensor at ignition ON and mode changes.
The range actuator position sensor is an integral part of the A16 Transfer Case Motor and cannot be replaced independently.
The transfer case range position sensor, also known as the gear position sensor, is an independently replaceable part.

• Faulty Transfer Case Motor (Transfer Case Two/Four Wheel Drive Actuator)
• Transfer Case Motor harness is open or shorted
• Transfer Case Motor circuit poor electrical connection
• Faulty Transfer Case Control Module