Engine Management Systems - Denso-am.eu

Engine Management SystemsMass Air FlowSensorsGBInstallation and fault-findingRemoval and installationAlways disconnect the cable from negative (-) batteryterminal before replacement and wait at least 90seconds after disconnecting the cable to preventany type of activation. After replacement, connect thecable to negative (-) battery terminal.1. Disconnect the MAF Sensor connector. Remove the screws andplug-in type MAF Sensor. If MAF Sensor has a suction pipe,loosen the pipe clamps that locate the MAF Sensor into the airintake duct and remove the MAF Sensor2. Install the new MAF Sensor with the screws into the air intakeduct and connect the MAF connector. If the MAF Sensor hasa suction pipe, tighten all pipe clamps. Turn the engine on andcheck if the intake system works properly3. Check the entire air intake system for leaks and make sure thatthe O-ring is not cracked or jammed when installing itTake care – the MAF Sensor is a delicate piece ofhardware that can be damaged when installingFault-findingPossible failures> MAF Sensor contamination or damage is usually caused by an AirFilter that is in poor condition or incorrectly installed. A damaged orcontaminated MAF Sensor can still function, but the changes to itscharacteristics can cause a wide variety of driving problemsSymptoms> Poor startup: First combustion occurs, but combustion isincomplete> Instability at idling: High idle speed, low idle speed or unstableidle> Poor drivability: Hesitation during acceleration, engine backfires,abnormal knocking or black smoke emitted> Stalling: Shortly after startup, when accelerator is depressed orreleasedPrevention and solutions> A problem with the MAF Sensor can cause the engine warninglight to turn on. This fault is stored as a diagnostic trouble code(DTC) in the engine ECU and can be inspected by a DTC scantool. However, if the root cause of failure is a clogged MAF Sensorpassage, the engine will usually start, will run poorly or stall, andmay not set a DTC> If the MAF Sensor is defective, it will need to be replaced. This is avery simple process. If the MAF Sensor is contaminated, cleaningit may provide a temporary solution; but this may damage theSensor’s delicate hardware. If the MAF Sensor is replaced, makesure the air filter is also installed properly15