Preliminary Procedure
- Connect NGS tester to Data Link Connector (DLC). Using NGS tester, perform DATA LINK DIAGNOSTIC TEST. If NGS tester does not communicate with vehicle, see MODULE COMMUNICATIONS NETWORK - PICKUP article in COMMUNICATIONS DEVICES to diagnose network.
- If NGS tester displays SYSTEM PASSED for GEM, retrieve and record continuous DTCs. Erase continuous DTCs. Perform GEM On-Demand self-test diagnostics using NGS tester. If any GEM DTCs are retrieved, perform appropriate test under SYMPTOM TESTS. See GENERIC ELECTRONIC MODULE (GEM) DTC INDEX table. If no DTCs are retrieved, perform appropriate test according to symptom. See SYMPTOM INDEX table under SYSTEM TESTS.