Malfunction Indicator Lamp: Description and Operation

CHECK ENGINE/MALFUNCTION INDICATOR LAMP




Among the on-board diagnostic items, a service engine soon/malfunction indicator lamp illuminates to notify the driver of the emission control items when a malfunction is detected. However, when an irregular signal returns to normal and the engine control module judges that it has returned to normal, the service engine soon/malfunction indicator lamp is switched off.
Moreover, when the ignition switch is turned off, the lamp is switched off. Even if the ignition switch is turned on again, the lamp does not illuminate until the malfunction is detected. Here, immediately after the ignition switch is turned on, the service engine soon/malfunction indicator lamp is lit for 5 seconds to indicate that the service engine soon/malfunction indicator lamp operates normally.

Items Indicated by The Service Engine Soon/Malfunction Indicator Lamp

P0100 - P0443:

P0442 - P1791:

NOTE
1. After the Engine Control Module (ECM) detects a malfunction, the service engine soon/malfunction indicator lamp illuminates when the engine is next turned on and the same malfunction is re-detected.
However, for items marked with a "*", the service engine soon/malfunction indicator lamp illuminates on the first detection of the malfunction.
2. After the service engine soon/malfunction indicator lamp illuminates, it will be switched off under the following conditions.

- When the ECM monitored the powertrain malfunction three times* and detected no malfunction.
*: In this case, one time indicates from engine start to stop.
- For misfiring or a fuel trim malfunction, when driving conditions (engine speed, engine coolant temperature, etc.) are similar to those when the malfunction was first recorded.

CAUTION: If the service engine soon/malfunction indicator lamp illuminates because of a malfunction of the ECM, transmission between the scan tool and the ECM cannot occur. In this case, the diagnostic trouble code cannot be read.