Is the third time the user to the station maintenance, the first two vehicles to the repair station after the inspection did not appear the user described the problem. Maintenance personnel connected to the fault diagnosis instrument on the engine control system for testing, equipment tips engine 3,4 cylinder fire.
    Through careful communication with the user that the car can not start the emergence of the fault is irregular, and there is no sign before the failure. In addition, after each failure, as long as waiting for some time, the vehicle can start normal. The user said the car once parked in the outdoor 1 night, the first day of the morning start when the fault occurs; a vehicle just stopped in the basement for half an hour, after the start of the failure; a vehicle flameout 10min, re-start when the failure occurs. This car has never been in the process of turning off the phenomenon, and each time the car can not run the engine can run. In addition, the user also stressed that there is a encounter when the vehicle can not start, no matter how the start will not work, but the vehicle in the parking day after the first 2 days but can start normal.
    For W221 vehicle engine normal start to meet the following conditions.
    (1) The driving license system is authorized. Electronic ignition switch EIS, engine control unit ME, electronic gearshift mechanism ASL, automatic transmission control unit ETC must confirm the legitimacy of the key and the vehicle gear information to allow the engine to start).
    (2) normal oil pressure, accurate speed signal and ignition system can be normal ignition.