The automatic transfer case Scan Tool Data Definitions contain a brief description of all transfer case related parameters available on the scan tool. The list is in the order it appears on the scan tool.

2WD High Indicator Light: This parameter displays On when the transfer case shift control module commands the 2WD high indicator light On. The scan tool displays On or Off.

4WD High Indicator Light: This parameter displays On when the transfer case shift control module commands the 4WD high indicator light On. The scan tool displays On or Off.

4WD Low Indicator Light: This parameter displays On when the transfer case shift control module commands the 4WD low indicator light On. The scan tool displays On or Off.

ATC Slip Speed: This parameter displays the RPM difference between the front and rear propshafts. The scan tool displays a range of 0-8,192 RPM.

Auto 4WD Indicator Light: This parameter displays On when the transfer case shift control module commands the auto 4WD indicator light On. The scan tool displays On or Off.

Commanded Mode Indicator:  This parameter displays which mode the shift control switch is currently requesting. The scan tool displays a range of Auto 4WD to 4WD Low.

Encoder Circuit A: This parameter displays whether the transfer case shift control module is sensing voltage on the Encoder Circuit A. The scan tool displays On when the transfer case shift control module senses voltage less than or equal to 1 Volt. The scan tool displays Off when the transfer case shift control module senses voltage greater than or equal to 3 volts.

Encoder Circuit B: This parameter displays whether the transfer case shift control module is sensing voltage on the Encoder Circuit B. The scan tool displays On when the transfer case shift control module senses voltage less than or equal to 1 Volt. The scan tool displays Off when the transfer case shift control module senses voltage greater than or equal to 3 volts.

Encoder Circuit C: This parameter indicates whether the transfer case shift control module is sensing voltage on the Encoder Circuit C. The scan tool displays On when the transfer case shift control module senses voltage less than or equal to 1 Volt. The scan tool displays Off when the transfer case shift control module senses voltage greater than or equal to 3 volts.

Encoder Circuit P: This parameter displays whether the transfer case shift control module is sensing voltage on the Encoder Circuit P. The scan tool displays On when the transfer case shift control module senses voltage less than or equal to 1 Volt. The scan tool displays Off when the transfer case shift control module senses voltage greater than or equal to 3 volts.

Encoder Gear Position: This parameter displays the mode the transfer case is currently in.

Front Axle Requested: This parameter displays Yes if the transfer case shift control module requests the front axle switch On. The scan tool displays Yes or No.

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

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

GM Part Number: This parameter displays the GM part number assigned to the module package: module, software, and calibrations. The scan tool displays a numeric value.

Ignition 3: This parameter displays the voltage measured by the transfer case shift control module at the transfer case shift control module ignition feed. The scan tool displays a range of 0-25.5 volts.

Last Adapt Highest PWM: This parameter displays the highest duty cycle applied to the transfer case encoder motor during the last slip event. The scan tool displays a range of 0-100 percent.

Mode Switch Selected: This parameter displays the transfer case shift control switch button currently depressed by the driver.

Neutral Indicator Light: This parameter displays On when the transfer case shift control module commands the neutral indicator light On. The scan tool displays On or Off.

Park Switch: This parameter displays the feedback states of the Park/Neutral switch. The scan tool displays Open or Closed.

Rear Propshaft Slippage: This parameter displays the total slippage of the rear propshaft. The scan tool displays a range of 0-8,192 RPM.

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

Service 4WD Lamp: This parameter displays On if the transfer case shift control module commands the Service 4WD lamp, or message, On. The scan tool displays On or Off.

Slip Adapt Mode: This parameter displays Enabled if the transfer case shift control module is currently attempting to prevent front-to-rear propshaft slip. The scan tool displays Enabled or Disabled.

Slip Adapt PWM: This parameter displays the duty cycle applied to the transfer case encoder motor. The scan tool displays a range of 0-100 percent.

Throttle Anticipation Mode: This parameter displays Enabled when the vehicle starts movement from a stop position, light-to-heavy throttle is applied, and is currently in AWD mode. Throttle Anticipation Mode helps eliminate the clunking sound normally associated with front axle engagement. The scan tool displays Enabled or Disabled.

Total Slippage: This parameter displays the total slippage of both the front and rear propshafts. The scan tool displays a range of 0-8,192 RPM.

TP Angle: This parameter displays a numeric value computed by the PCM from the TP sensor voltage. The TP Angle should rear 0 percent at idle and 100 percent at Wide Open Throttle (WOT). The scan tool displays a range of 0-100 percent.

Transfer Case Lock: This parameter displays Enabled if the transfer case shift control module commands the transfer case motor brake On. The scan tool displays Enabled or Disabled.