Retrieving Diagnostic Trouble Codes Using Mil (Q45 Only): Notes

NOTE: CHECK ENGINE or SERVICE ENGINE SOON light is now referred to as Malfunction Indicator Light (MIL).

Turn ignition on. Verify MIL is properly illuminated. If MIL does not illuminate, repair MIL circuit. See WIRING DIAGRAMS article. Turn mode selector switch on ECM fully clockwise. MIL should turn off. Wait 2 seconds, and turn mode selector fully counterclockwise. System is now in Diagnostic Test Mode II. Retrieve Diagnostic Trouble Codes (DTCs) by observing MIL, and counting the number of flashes. Record all codes set and then go to appropriate test procedure. MIL DTC numbering is different than CONSULT or scan DTC numbering. See DIAGNOSTIC TROUBLE CODE (DTC) IDENTIFICATION (Q45) table.