Malfunction Indicator Lamp: Testing and Inspection

Items Indicated by the Check Engine/Malfunction Indicator Lamp








As a functional test, the malfunction indicator lamp (MIL) illuminates at key-on before engine cranking.
Whenever the Powertrain Control Module (PCM) sets a diagnostic trouble code that effects vehicle emissions, it illuminates the MIL. The PCM illuminates the MIL only for diagnostic trouble codes that effect vehicle emissions. The MIL remains on until the diagnostic trouble code is erased.
On manual transaxle vehicles, the MIL either flashes or illuminates continuously when the PCM detects active engine misfire.
During active misfire, the PCM records the current engine operating conditions. The engine operating conditions are recorded by the PCM.

NOTE:
1. After the PCM detects a malfunction, the check engine/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 check engine/malfunction indicator lamp illuminates on the first detection of the malfunction.
2. After the check engine/malfunction indicator lamp illuminates, it will be switched off under the following conditions.
- When the PCM 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 check engine/malfunction indicator lamp illuminates because of a malfunction of the PCM, transmission between the scan tool and the PCM cannot occur. In this case, the diagnostic trouble code cannot be read.