Scan Tool Data Definitions

The Automatic Transfer Case (ATC) Scan Tool Data Definitions contain a brief description of all ATC related parameters available on the scan tool. The scan tool data list is arranged in alphanumeric order.
ATC Slip Speed: The scan tool displays a range of 0-8192 RPM. This parameter indicates the RPM difference between the front and rear propshafts.
Auto 4WD Indicator Light: 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.
Commanded Mode Indicator: The scan tool displays a range of Auto 4WD to 4WD Low. This parameter indicates the current mode in which ATC is operating.
Encoder Circuit A: The scan tool displays On or Off. This parameter indicates whether transfer case shift control module is sensing voltage on the Encoder Circuit A (On=<1 Volt, Off=>3 Volts).
Encoder Circuit B: The scan tool displays On or Off. This parameter indicates whether transfer case shift control module is sensing voltage on the Encoder Circuit B (On=<1 Volt, Off=>3 Volts).
Encoder Circuit C: The scan tool displays On or Off. This parameter indicates whether transfer case shift control module is sensing voltage on the Encoder Circuit C (On=<1 Volt, Off=>3 Volts).
Encoder Circuit P: The scan tool displays On or Off. This parameter indicates whether transfer case shift control module is sensing voltage on the Encoder Circuit P (On=<1 Volt, Off=>3 Volts).
^ Encoder Gear Position: The scan tool displays a range of Auto 4WD to 4WD Low. This parameter indicates the actual transfer case sector shaft position as sensed by the encoder.
^ Front Axle Switch: The scan tool displays Locked or Unlocked. This parameter indicates the feedback states of the front axle switch.
^ Front Axle Switch 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 Propshaft Speed: The scan tool displays a range of 0-8192 RPM. This parameter indicates the rotational speed of the front propshaft.
^ GM Part Number: The scan tool displays an eight-digit number. This parameter indicates the transfer case shift control module GM software number.
^ Ignition 3: 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 its ignition feed.
^ Last Adapt Highest PWM: The scan tool displays a range of 0-100 %. This parameter indicates the highest duty cycle applied to the ATC motor during the last slip event.
^ Mode Switch Selected: The scan tool displays On or Off. This parameter indicates the ATC mode switch button currently depressed by the driver.
^ Neutral Indicator Light: 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.
^ Park Switch: The scan tool displays Open or Closed. This parameter indicates the feedback states of the Park/Neutral Switch.
^ Rear Propshaft Speed: The scan tool displays a range of 0-8192 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 indicator (AWD/4WD) Lamp is being commanded by the transfer case shift control module.
^ Slip Adapt Mode: The scan tool displays Enabled or Disabled. This parameter indicates if the transfer case shift control module is currently attempting to prevent front to rear propshaft slip.
^ Slip Adapt PWM: The scan tool displays a range of 0-100 %. This parameter indicates the duty cycle applied to the ATC motor.
^ Software ID: The scan tool displays a four-digit number. This parameter indicates the transfer case shift control module calibration version number.
^ Throttle Position (TP) Angle: The scan tool displays a range of 0-100 %. The TP Angle is computed by the PCM from the TP sensor voltage. The TIP Angle should read 0 percent at idle and 100 percent at Wide-Open Throttle (WOT).
^ 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 Light: 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 Light: 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 Lamp Open: The scan tool displays Yes or No. This parameter indicates if the 4WD Lamp circuit is open or shorted to ground, when a Yes is displayed.
^ 4WD Lamp Shorted: The scan tool displays Yes or No. This parameter indicates if the 4WD Lamp circuit is shorted to voltage or a loss of driver ground, when a Yes is displayed.
^ 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.