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NAG1 PRE-DIAGNOSTIC TROUBLESHOOTING PROCEDURE For a complete wiring diagram Refer to Section 8W Perform the following pre-diagnostic troubleshooting procedures prior to performing any diagnostic test. Low fluid level can be the cause of many transmission problems. If the fluid level is low, locate and repair the leak Always perform diagnostics with a fully charged battery to avoid false symptoms. 1. With the scan tool, read the engine DTCs. Check and repair all engine DTCs prior to performing transmission symptom diagnostic procedures. 2. With the scan tool, read and record all Transmission DTCs. NOTE: If the TCM detects and stores a DTC, the TCM also stores the vehicles operating conditions under 3. Using the wiring diagram/schematic as a guide, inspect the wiring and connectors. Clean and repair as neces- sary. 4. Most DTCs set on start up but some must be set by driving the vehicle such that all diagnostic monitors have run. 5. Verify flash level of transmission controller. Some problems are corrected by software upgrades to the transmis- sion controller. Verify that no variant DTCs are present. If variant DTCs are present, perform their respective test 6. If the TCM (EGS) is flashed, perform a EGS initialization with the scan tool to relearn variant coding. 7. Check for any Service Information Tune-ups or Service Bulletins that may apply. 1. Did any of the above procedures repair the vehicle? Yes >> Testing is complete. Perform NAG1 TRANSMISSION VERIFICATION TEST. (Refer to 21 - TRANSMISSION/TRANSAXLE/ No >> Refer to the identified category and perform the appropriate symptom(s). (Refer to 21 - TRANSMISSION/TRANSAXLE/AUTOMATIC - 42RLE - DIAGNOSIS AND TESTING) 21 - 218 AUTOMATIC TRANSMISSION NAG1 - ELECTRICAL DIAGNOSTICS LX |