Diagnostic Circuit Check
The Diagnostic Circuit Check is a starting point to identifying a problem caused by the fuel injection system.
NOTE:
Test numbers refer to test numbers on diagnostic chart.
- If CHECK ENGINE light illuminates with ignition on and engine stopped, this confirms battery and ignition voltage to the ECM.
- The ECM flashes Code 12 with the CHECK ENGINE light. This indicates ECM diagnostics are working. Code 12 will not flash 3 times if other codes are stored in memory. Each additional code flashes 3 times. Codes start with the lowest code. If no codes are present, Code 12 flashes until fuse is removed from fuse box.
- Record all codes stored except Code 12. If vehicle problem is engine cranks but will not run, see BASIC TESTING article.
- If no additional codes were recorded, refer to TESTS W/O CODES article.