Scan Tool Set-Up and Functionality

When performing powertrain diagnostics on OBD II vehicles, the system may be checked by an off board tester referred to as a scan tool. This section contains instructions for performing diagnostics with the New Generation Star (NGS) Tester scan tool and the Generic Scan Tool (GST). A GST has a capability that is standard across the automotive industry in the United States. However, to perform manufacturer-specific functions, a string of characters must be entered manually. If a NGS is used, those functions are selected from a menu.

New Generation STAR Hookup With Cable Assembly:

PROCEDURES
New Generation STAR (NGS) Tester:

1. key OFF.
2. Verify that the proper memory (EPROM) card is inserted in the NGS.
3. Connect OBD II Data Link Connector (DLC) cable, or Villager DLC cable to the NGS.
4. Connect OBD II DLC cable securely into the OBD II DLC, for generic diagnostics or the Villager DLC cable for expanded diagnostics.
5. Connect the NGS power supply cable to vehicle.
6. Turn key to ON or start vehicle if necessary. The NGS is ready to communicate with vehicle computers.
7. Follow instructions on the NGS screen display.
8. To disconnect tool, turn key to OFF and disconnect NGS from the appropriate DLC and power supply.

Location
The OBD II DLC is located in the passenger compartment. It is attached to the instrument panel and accessible from the driver seat.

Description
The OBD II DLC is rectangular in design and capable of accommodating up to 16 terminals. The connector has keying features to allow easy connection. The vehicle connector and the test equipment connector have latching features that ensure the test equipment connector will remain mated when properly connected.





Communication Error
It is possible to get a communication error from a scan tool when initiating a diagnostic test or accessing Parameter Identifications (PIDs). The communication error could be caused by operator error, the vehicle wiring, connectors, the powertrain control module (PCM) or other control modules connected to the OBD II DLC wiring. The PCM will respond to a scan tool whenever the tool requests a test. If manually entering the message strings using a generic scan tool, the numeric codes will be at the end of the string of characters. These are not diagnostic trouble codes (DTCs). Listed below are some of the numeric codes and generic descriptions that a scan tool may display when trying to perform some PCM operations. It is possible to get other numeric codes not listed.
For a complete list of communication response codes, refer to Society of Automotive Engineers (SAE) document J2 190 enhanced E / E Diagnostic Test Modes. Some are normal responses to valid requests. The others are communication error responses.