Test Equipment

Test Equipment
The New Generation Star (NGS) Tester or equivalent:
^ Allows individual commands for inputs and outputs of the Generic Electronic Module (GEM) System.
^ Allows retrieval of Diagnostic Trouble Codes (DTCs) from the GEM.
All testing in this manual can be accomplished using the NGS.

ISO 9141-Data Link Connector (DLC):

DTCs are reported to the NGS through the Data Link Connector (DLC). DTCs are cleared manually by the NGS or after a planned period of time not seeing the same DTC (e.g., 80 start cycles) by the GEM.

Continuous Diagnosis
An integral part of the normal GEM operation is the Continuous Diagnostics capability. Continuous Diagnostics detects faults and manages them by changing the GEM control strategy. Following are examples of faults that can be detected during the normal operating mode:
^ GEM continuous self test
^ Output driver monitoring (ground and battery)
^ Illogical input signals
Action that may be taken by continuous diagnostics are as follows:
^ Manage the fault
^ Store a diagnostic trouble code
^ Illuminate a warning lamp

GEM Diagnostics Mode
The GEM diagnostics mode has the ability to interface with you via the NGS. This diagnostic operation allows the best fault isolation capability. You have the ability to communicate with the GEM subsystem when the NGS is in the diagnostics mode. Interaction with the GEM is achieved by the following:
^ Requesting the GEM to perform tasks (e.g., turn ON the wipers)
^ Transmitting GEM control states (e.g., switch status)
^ Physically interacting (e.g., connecting/disconnecting wires) with the vehicle hardware

The tester has a menu-driven user interface allow you the ability to run a specific diagnostic test. You can separate faults in the GEM through a symptom-driven diagnostic process, exercising specific functional tests, or retrieving DTCs.

The majority of the GEM diagnostic strategy is in the GEM. The NGS requests the GEM for input and output status. It then sends commands to actuate the output devices and has the GEM run diagnostic tests and report stored DTCs.