Chart A-2, Won't Flash Code 12, Or Any Codes, Mil On Steady

Malfunction Indicator Light (MIL) will flash trouble codes when either diagnostic request terminal in duty check data link connector or DIAG SW connector in fuse block is grounded.

NOTE: Test numbers refer to test numbers on diagnostic chart.

Checks for a grounded light circuit.
Checks if problem is an open circuit in diagnostic terminal or a faulty ECM.

Fig 1: Chart A-2 Schematic Won't Flash Code 12 Or Any Codes, MIL On steady

Fig 2: Chart A-2 - Flow Chart Won't Flash Code 12 Or Any Codes, MIL On steady