GM Service Manual Online
For 1990-2009 cars only
ATC Application: The scan tool displays a numeric value. This parameter indicates the model number assigned to the transfer case.

ATC Software ID: The scan tool displays a numeric value. This parameter indicates the numbers or characters assigned to the current version of software used in the ATC module.

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

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.

Current Slip Adapts: The scan tool displays a numeric value. This parameter indicates corrective adjustments made by the transfer case shift control module for wheel slip events.

Encoder Gear Position: The scan tool displays the different modes, Auto 4WD, 2WD High, 4WD High, 4WD Low, and Neutral. This parameter indicates the current mode 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 encoder power.

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.

Front Propshaft Speed: The scan tool displays a range of 0-8,192 RPM. This parameter indicates the rotational speed 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 Current: The scan tool displays Amps. This parameter indicates current flow when the motor moves one of two directions.

Motor B Current: The scan tool displays Amps. This parameter indicates current flow when the motor moves one of two directions.

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.

Rear Propshaft Speed: The scan tool displays a range of 0-8,192 RPM. This parameter indicates the rotational speed of the rear propshaft.

Service 4WD Lamp: 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.

Slip Adapt PWM: The scan tool displays a range of 0-100 percent. This parameter indicates the Duty Cycle applied to the ATC motor.

Total Slippage: The scan tool displays a range of -32,767 to +32,767 RPM. This parameter indicates the total slippage of both the front and rear propshafts.

Transfer Case Lock: The scan tool displays Enabled or Disabled. This parameter indicates if the transfer case shift control module is commanding the transfer case motor brake ON.

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 Light: 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.