Malfunction Indicator Light Inspection: Operation

When ignition is turned on without starting the engine, MIL should illuminate. If MIL does not illuminate, go to MALFUNCTION INDICATOR LIGHT DIAGNOSIS in TROUBLE SHOOTING - NO CODES article. After starting engine, MIL light should go out. If MIL does not go out, go to HARD FAILURES  . If DTC does not exist, go to MALFUNCTION INDICATOR LIGHT DIAGNOSIS in TROUBLE SHOOTING - NO CODES article.

Under normal operation, MIL will illuminate as a bulb check when ignition is turned on and go out when vehicle is started. If a malfunction is detected, the light will be illuminated. See HARD FAILURES  and INTERMITTENT FAILURES  to determine type of malfunction detected. MIL will also illuminate if fuel filler cap is not properly installed after filling tank. Check fuel filler cap before proceeding with any diagnostics. If an ignition misfire is detected, MIL will blink at a cycle of 1 Hz.

When diagnostic test mode connector under dash is connected together when ignition is on (engine not running) or in START position, MIL will blink at a cycle of 3 Hz. If MIL does not blink at a cycle of 3 Hz, go to MALFUNCTION INDICATOR LIGHT DIAGNOSIS in TROUBLE SHOOTING - NO CODES article. If MIL continues to blink at a rate of 3 Hz after diagnostic test connectors are disconnected, go to MALFUNCTION INDICATOR LIGHT DIAGNOSIS in TROUBLE SHOOTING - NO CODES article.