Malfunction Indicator Lamp: Description and Operation

During normal engine operation, the dashboard mounted ``Check Engine'' lamp is off.
If a problem develops in the ``Closed Loop Emission Control System'' while the engine is running, the ``Check Engine'' lamp will light and a trouble code will be stored in the ECM. The light will remain lit as long as there is a problem and the engine is running. If the problem should clear up, the ``Check Engine'' lamp will go out, but a trouble code will be stored in the ECM. If the ``Check Engine'' lamp is On or was On, refer to System Self-Diagnosis.
With the ignition switch On with the engine not running, the ``Check Engine'' lamp should light as a bulb test.