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 a range of Auto 4WD to 4WD Low. This parameter indicates the current mode in which the ATC is operating.

Encoder Return 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 encoder signal return.

Encoder Supply 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 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 0-25.5 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 0-8,192 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.