GM Service Manual Online
For 1990-2009 cars only
Battery Voltage: The scan tool displays a range of 0-25.5 volts. This parameter indicates the voltage measured by the transfer case shift control module at the battery feed.

Encoder Gear Position: This parameter indicates the current mode and range in which the ATC is operating.

Encoder Return Voltage: The scan tool displays a range of 0-5 volts. This parameter indicates the voltage measured by the transfer case shift control module at the encoder signal return.

Encoder Supply Voltage: The scan tool displays a range of 0-7.5 volts. This parameter indicates the voltage measured by the transfer case shift control module at the 8 V reference circuit.

Front Axle Requested: The scan tool displays YES or NO. This parameter indicates if the front axle switch has been requested by the transfer case shift control module.

Front Axle Switch: The scan tool displays Locked or Unlocked. This parameter indicates the feedback states of the front propshaft.

Ignition Cycles Since Last Current DTC: The scan tool displays a numeric value. This parameter indicates how many ignition cycles have occurred since last current DTC was set.

Mode Switch Return Voltage: The scan tool displays a range of 0-5 volts. This parameter indicates the return voltage from the mode switch.

Mode Switch Selected: The scan tool displays ON or OFF. This parameter indicates the ATC mode switch button currently depressed by the driver.

Motor A/B Current: The scan tool displays the actual current flowing through the circuit.

Neutral Indicator: The scan tool displays ON or OFF. This parameter indicates if the Neutral Indicator Light is being commanded by the transfer case shift control module.

Service 4WD Indicator: The scan tool displays ON or OFF. This parameter indicates if the Service 4WD lamp is being commanded by the transfer case shift control module.

2WD High Indicator: The scan tool displays ON or OFF. This parameter indicates if the 2WD high indicator light is being commanded by the transfer case shift control module.

4WD High Indicator: The scan tool displays ON or OFF. This parameter indicates if the 4WD high indicator light is being commanded by the transfer case shift control module.

4WD Low Active: The scan tool displays YES or NO. This parameter indicates whether or not the 4WD Active mode is active.

4WD Low Indicator: The scan tool displays ON or OFF. This parameter indicates if the 4WD low indicator light is being commanded by the transfer case shift control module.