Example 1
    Symptom: A Lexus RX300. Models for the MCU35L, reported idle speed jitter, acceleration bad. The car has failed three months, repair many times.
    Troubleshooting: Remove the car intake manifold, replace the spark plug and high voltage lines, start the car, the fault exists, again the original car spark plug and the main pressure line back.
    Turn the ignition switch to the ON position, the engine fault light is on; the car, the engine fault light goes out. Idle, the combustion is poor, the engine jitter, refueling slow. With the diagnostic device to detect the engine system data flow, the engine idling into 650R / min, the fuel injection pulse width of 3.5ms, high; sensor parameter data is normal, the system is in the oil state, no fault code.
    Broken cylinder experiment found that the third cylinder does not work. Idle, unplug the third cylinder ignition coil plug, the engine fault light, the fault code for the P0353, which means the third cylinder ignition coil primary / secondary line failure, indicating the third cylinder ignition coil normal. Exchange the third cylinder and other cylinder between the ignition coil, is still the third cylinder cylinder, indicating that the ignition coil is good, indicating that the ignition system is faulty, the fault appears in the injector.
    Detection of the third cylinder injector resistance and line, normal. Start the car, hand touch the first 3 cylinder injector, found that it does not work. Turn off the ignition switch to the OFF position, return to the ON position, the engine stops, the third cylinder injector control line (black) ground, hear the third cylinder injector "despair" sound, that injector action. Start the car, with a diagnostic device to detect the fuel injection control line voltage waveform, the third cylinder voltage waveform for a power supply voltage of the straight line. Description of the engine ECU and the line on the third cylinder injector is not controlled. The engine control system line to conduct a thorough inspection, normal.
    Then, it is determined that the engine ECU is damaged. Engine ECU price is too expensive, it is required to repair the engine ECU, then open the engine ECU, for maintenance.
    Idle, the control voltage for the power supply voltage, pull out the first 3-cylinder injector plug, detection control very control signal output. Unplug the engine ECU plug, detect this transistor for the NPN-type transistor, the control electrode (base) and the injector control line side (collector) between the breakdown short circuit.
    As the injector work instantly up to nearly 100 volts of induction voltage, beyond the general household appliances class electronic component voltage, and the need for power switching transistor (NPN type) can be replaced, so the replacement parts are not easy to find. Suddenly thought of the previously renovated 220V AC fluorescent lamp circuit has a pair of requirements to meet the requirements of the push-pull transistor, and the scrapped the lamp circuit board, so from the scrapped fluorescent circuit board to remove a transistor, numbered D618C4D52, as a replacement. After testing, the replacement performance is good. Due to the poor shape of the poor, the engine ECU circuit board damage to the transistor, and from the phase of the position leads to three lines, respectively, welded on the end of the replacement parts.