Overview and Preparation

The tester-dependent diagnostics mode allows communication with the GEM through the NGS Tester. Diagnostic testing is controlled by turning on outputs, reading inputs, retrieving DTCs, clearing DTCs, direct memory reference and initiating functional tests.
The On-Demand Self Test consists of a module self test and a GEM subsystem input/output self test. Continuous DTCs are not affected when running an On-Demand Self Test.

NOTE: Do not press any buttons or switches during the On-Demand Self Test.

The On-Demand Self Test requires the following vehicle conditions:
- all doors closed
- key in RUN.
- multi-function switch is in the OFF position and the windshield wiper blades parked
- head lamps OFF
- all windows up
- liftgate closed
- seat belts unbuckled