The scan tool provides the following capabilities:
| • | Displays the data list. |
| • | Displays current and history trouble codes. |
| • | Clear the diagnostic trouble codes after a repair is completed. |
Important: Make sure the scan tool that you are using is functioning properly and has the latest software. Use of a malfunctioning scan tool or one that has old software can result in misdiagnosis and unnecessary parts replacement.
To use the scan tool, connect it to the Data Link Connector (DLC) and turn the ignition switch to the RUN position.
The Transfer Case Scan Tool Data List contains all the automatic transfer case (ATC) related parameters that are available on the scan tool. The scan tool data list is arranged in alphanumeric order.
Use the Transfer Case Scan Tool Data List only after the following is determined:
| • | A Diagnostic System Check has been completed. |
| • | No Diagnostic Trouble Codes (DTCs) are set. |
| • | Transfer case diagnostic tables indicate the system is functioning properly. |
Scan tool values from a properly operating system may be used for comparison with the transfer case system you are diagnosing. The Transfer Case Scan Tool Data List represents values recorded under the following conditions:
| • | Engine is at idle |
| • | Closed throttle |
| • | Gear is in PARK or NEUTRAL |
| • | Accessories are OFF |
Only the parameters listed below are referenced in this service manual for use in diagnosis. If all values are within the typical range described below, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems for further diagnosis.
Scan Tool Parameter | Data List | Units Displayed | Typical Data Value |
|---|---|---|---|
Engine is at Idle, Upper Radiator Hose Hot, Closed Throttle, Gear is in Park or Neutral, and Accessories are OFF. | |||
ATC Slip Speed | Data Display | RPM | 0 |
Auto 4WD Indicator Light | Data Display | On/Off | On |
Commanded Mode Indicated | Data Display | 2WD/4WD High/4WD Low/Auto 4WD | Varies |
Encoder Circuit A | Data Display | On/Off | Off |
Encoder Circuit B | Data Display | On/Off | On |
Encoder Circuit C | Data Display | On/Off | Off |
Encoder Circuit P | Data Display | On/Off | On |
Encoder Gear Position | Data Display | 2WD/4WD High/4WD Low/Auto 4WD | Varies |
Front Axle Switch | Data Display | Locked/Unlocked | Locked |
Front Axle Switch Requested | Data Display | Yes/No | Yes |
Front Propshaft Speed | Data Display | RPM | 0 |
GM Part Number | Data Display | Number | Varies |
Ignition 3 | Data Display | Volts | Battery Voltage |
Last Adapt Highest PWM | Data Display | % DC | 0 |
Mode Switch Selector | Data Display | On/Off | Off |
Neutral Indicator Light | Data Display | On/Off | Off |
Park Switch | Data Display | Closed/Open | Closed |
Rear Propshaft Speed | Data Display | RPM | 0 |
Rear Slippage | Data Display | RPM | 0 |
Service 4WD Lamp | Data Display | On/Off | Off |
Slip Adapt Mode | Data Display | Enabled/Disabled | Disabled |
Slip Adapt PWM | Data Display | % DC | 0 |
Software ID | Data Display | Number | Varies |
TP Angle | Data Display | % | 0 |
Throttle Anticipation Mode | Data Display | Enabled/Disabled | Disabled |
Transfer Case Lock | Data Display | Enabled/Disabled | Enabled |
2WD High Indicator Light | Data Display | On/Off | Off |
4WD High Indicator Light | Data Display | On/Off | Off |
4WD Lamp Open | Data Display | Yes/No | No |
4WD Lamp Shorted | Data Display | Yes/No | No |
4WD Low Indicator Light | Data Display | On/Off | Off |
