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Feb 092015
 

Error code PO171 appeared and I am starting out with ordering an 02 sensor, fuel filter, plugs, and pcv. Car was driving ok while awaiting for parts to arrive, when I went to start the car, it took a very long time to start, and when it did, it conked out after stepping on the gas pedal. I know the problems aren’t linked, but don’t know where to start with the starting problem.

  One Response to “2002 audi a4 quatro turbo awd 1.8L 5spd man”

  1. The problems may very well be linked. In sounds like it is fuel related to me. Try having someone spray stating fluid in the air filter while you start it and see if you can keep it running on the starting fluid. This lets you know it is for certain fuel related. You may have an intake leak and a sensor bad (MAF – MASS AIR FLOW SENSOR)that is shutting off the fuel. You can also try cycling the key, holding it on the “ON” position for a few seconds. Do this 10 times as it will prime the fuel lines and see if it starts easier. This would let you know if the fuel pressure is bleeding off( possible leaking fuel pressure regulator and or internal fuel pump leak.)

    P0171 Audi – System Too Lean Bank 1

    Possible causes
    – Intake air leaks
    – Faulty front heated oxygen sensor
    – Ignition misfiring
    – Faulty fuel injectors
    – Exhaust gas leaks
    – Incorrect fuel pressure
    – Lack of fuel
    – Faulty Mass Air Flow (MAF) sensor
    – Incorrect Positive Crankcase Ventilation (PCV) hose connection

    When is the code detected?
    – Fuel injection system does not operate properly.
    – The amount of mixture ratio compensation is too small. (The mixture ratio is too lean.)

    P0171 Audi Description
    With the Air/Fuel Mixture Ratio Self-Learning Control, the actual mixture ratio can be brought closely to the theoretical mixture ratio based on the mixture ratio feedback signal from the heated oxygen sensors 1. The Engine Control Module (ECM) calculates the necessary compensation to correct the offset between the actual and the theoretical ratios.

    In case the amount of the compensation value is extremely large (The actual mixture ratio is too lean.), the ECM judges the condition as the fuel injection system malfunction and light up the Malfunction Indicator Light (MIL) (2 trip detection logic).

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