Check Engine Light
WARNING: This page does not describe the selected car, but rather 18 other vehicles, including the 2002 Mercedes-Benz CL500, 2001 Mercedes-Benz CL500, 2000 Mercedes-Benz SL500, 2000 Mercedes-Benz S430, and 2000 Mercedes-Benz ML55. However, it is still accessible from the selected car via links, so may be relevant.
The ECM is equipped with Diagnostic Trouble Code (DTC) memory. Malfunctions are stored as constantly present or intermittent (occurred during a trip). DTC memory is erased when battery is disconnected. Malfunctions which are no longer present are erased as follows: after 3 trips CHECK ENGINE light goes out and after an additional 40 warm-up periods, DTC is automatically erased.
A warm-up period is defined as engine coolant temperature less than 95°F (35°C) at engine start with engine coolant temperature increasing to more than 158°F (70°C). A trip is defined as follows:
- Engine running for more than 20 minutes
- Engine oil temperature more than 19°F (-7°C)
- Engine speed more than 500 RPM
- All emission related logic chain functions were checked during previous trips