A4: Engine System Check: Notes

The Engine System Check is the starting point for any driveability complaint diagnosis. The Engine System Check is an organized approach to identifying problems created by an electronic engine control system malfunction. Before any DTC(s) are retrieved, perform a visual underhood inspection, checking battery and grounds for clean and tight connections. Check for poor connections or damage to wiring harness and electrical connectors. Check for corroded terminals or corrosion buildup on any connection. If problem is found, repair as necessary. If no problem is found during initial inspection perform Engine System Check.