NVG 136 Transfer Case

CIRCUIT DESCRIPTION
The rear transfer case vehicle speed sensor generates the Rear Propshaft Speed as shown by the scan tool. The rear transfer case vehicle speed sensor is a Permanent Magnet (PM) generator. The PM generator produces a pulsing AC voltage. The AC voltage level and number of pulses increases as speed increases. The transfer case shift control module converts the pulsating AC voltage from the vehicle speed sensor to a Rear Propshaft Speed in RPM to be used for calculations. The Rear Propshaft Speed can be displayed with a scan tool.
This DTC detects an open, short to ground, or faulty sensor.

CONDITIONS FOR SETTING THE DTC
The system will log the Diagnostic Trouble Code (DTC) if the Rear Propshaft Speed input indicates a speed of less than 16 RPM for 30 seconds while all of the following are true:
- Transmission NOT in PARK or NEUTRAL
- Engine is running
- Front Propshaft Speed exceeds 512 RPM
- VCM monitored Vehicle Speed On Class 2 Data bus exceeds 10 mph

ACTION TAKEN WHEN THE DTC SETS
The system will not allow any further adaptive events (correct slip). The SERVICE AWD/4WD lamp will be latched on for the remainder of the current ignition cycle.

CONDITIONS FOR CLEARING THE DTC
- Current DTC
The transfer case shift control module will clear the DTC if the condition for setting the DTC no longer exists.
- History DTC
- Once 100 consecutive ignition cycles without a fault present.
- A scan tool CLEAR CODES command.

DIAGNOSTIC AIDS
An intermittent problem may be caused by a poor connection, break in the wire insulation exposing the internal wire, or a wire that is broken inside the insulation.