Symptom:
    A Mercedes-Benz sedan, in the process of driving, acceleration, throttle close to full open, the speed can not exceed 30kM / h, even when the high-speed failure is rare, mainly in the parking, start, and then accelerate the process of intermittent occurred.
    Failure analysis:
    Usually turn off the ignition switch, the engine stalled, and then open the ignition switch, start the engine, the fault disappears, to speed up the normal, car driving two or three days failure will reproduce. This car has some manufacturers overhaul and replaced the water temperature sensor, crankshaft position sensor and oxygen sensors and other components, the fault is not ruled out. Using SCANNER diagnostic equipment inspection, enter the OBD-11 diagnostic mode, first read the engine system fault code, shown as POOOO, no fault code: and then enter the numerical analysis, start the vehicle road test. The beginning of all the normal driving, and then to brake, parking, rapid acceleration and repeated trial several times to make the fault occurs, the road test more than an hour after the fault phenomenon to reproduce the throttle step in the end is still less than 30kM / h, Box SCANNER read failure is still P0000 no fault, the value of the analysis found two clues;
    Troubleshooting:
    The failure phenomenon reflects the car suddenly changed the fuel in the running correction mode, suddenly change the ignition advance angle, indicating that the engine has been poor control of the computer. This fault is replaced by the engine control computer after thorough elimination.