Mode Sensor

SENSOR-MODE

DESCRIPTION





The transfer case mode sensor (2) provides the Front Control Module (FCM) feedback about the position of the transfer case. The sensor consists of a linear analog position sensor that converts the motor output shaft position into a DC signal. The sensor may rotate a full 360 degrees for both the NV144 and the NV244 GENII. The operating envelope or sector rotation is -5 to 180 degrees for the NV144 and -40 to 20 degrees for the NV244 GENII. The FCM must supply 5VDC (+/- 0.5v) to the sensor whenever the FCM is not in sleep mode and monitor the shift motor position. The sensor position is monitored when the ignition is in the RUN position and for 10 seconds after the ignition is shifted to the OFF position. The sensor is mechanically linked to the shaft of the cam which allows the transfer case to shift. The mode sensor will draw less than 20 mA of current during operation.

OPERATION
During normal vehicle operation, the Front Control Module (FCM) monitors the mode sensor outputs at least every 2 milliseconds when the shift motor is stationary or active.

Refer to SHAFT ANGLE vs. TRANSFER CASE POSITION for the relative angles of the transfer case shift sector versus the interpreted transfer case gear operating mode.





SHAFT ANGLE vs. TRANSFER CASE POSITION

Note: All the parameter voltages referred to in the following information are calibrated items in the controller software and are subject to change.

Note: For a further explanation of Phase 1 through 3 shifting, Refer to TRANSFER CASE CONTROL MODULE - OPERATION.

The following information describes the different mode sensor positions:
- 4LOCK TARGET REGION - The position shall be considered 4LOCK if the voltage is greater than or equal to encoder 4LOCK min Volts and it is also less than or equal to encoder 4LOCK max Volts.
- AWD TARGET REGION - The position shall be considered AWD if the voltage is greater than or equal to encoder AWD_min Volts and it is also less than or equal to encoder AWD_max Volts.
- AWD SHIFT LIMIT - During Phase 2 and Phase 3 shifting, shifts may become unidirectional when a voltage is greater than or equal to encoder AWD_min Volts has been reached.

The mode sensor position will be considered invalid by the FCM if the voltage is greater than or equal to encoder_High_Range_Limit Volts or if it is less than or equal to encoder Low Range_Limit Volts.

If FCM looses the encoder signal in a NV144 transfer case during a shift, the FCM will respond with a shift back in the opposite direction of travel to first attempt to find the encoder signal. If the signal is not found, the FCM will drive motor in AWD direction for 1 second.

Refer to MODE SENSOR VOLTAGES - NV144 table for the mode sensor voltages.





MODE SENSOR VOLTAGES - NV144