Jul 302014
 

After exactly 90 seconds after start up the engine fluctuates for a few seconds hunting for air, I get P0101, P0102 and P0172 code. MAF is fine and I checked for leaks.

  One Response to “Mercedes C180 203 W203 M271 engine”

  1. After looking at the codes(info posted below)I first look to see what is in common with all the codes. Now for what ever reason the cars engine is running rich and the most common reason for this would be from a vacuum leak. could be a loose connection around a hose the air filter hoses, MAF hoses, intake gasket leak, etc.

    P0101 Mercedes-Benz – Mass or Volume Air Flow Circuit Range/Performance Problem

    Possible causes
    – Faulty mass air flow sensor
    – Intake air leaks
    – Dirty mass air flow sensor
    – Dirty mass air filter
    – Mass air flow sensor harness is open or shorted
    – Mass air flow sensor circuit poor electrical connection

    Possible symptoms
    – Engine Light ON (or Service Engine Soon Warning Light)
    – Engine stall
    – Engine running rough
    – Excessive fuel consumption
    – Excessive smoke

    P0101 Mercedes-Benz Description

    The Mass Air Flow (MAF) sensor is placed in the stream of intake air. It measures the intake flow rate by measuring a part of the entire intake flow. It consists of a hot film that is supplied with electric current from the Engine Control Module (ECM).

    The temperature of the hot film is controlled by the ECM a certain amount. The heat generated by the hot film is reduced as the intake air flows around it. The more air, the greater the heat loss. Therefore, the ECM must supply more electric current to maintain the temperature of the hot film as air flow increases. The ECM detects the air flow by means of this current change.

    P0102 Mercedes-Benz – Mass or Volume Air Flow Circuit Low Input
    Possible causes
    – Faulty mass air flow sensor
    – Intake air leaks
    – Dirty mass air flow sensor
    – Dirty mass air filter
    – Mass air flow sensor harness is open or shorted
    – Mass air flow sensor circuit poor electrical connection

    and basically the same as P0101

    P0172 Mercedes-Benz – System Too Rich Bank 1

    Possible causes
    – Faulty front heated oxygen sensor
    – Ignition misfiring
    – Faulty fuel injectors
    – Exhaust gas leaks
    – Incorrect fuel pressure
    – Faulty Mass Air Flow (MAF) sensor

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

    P0172 Mercedes-Benz 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 MIL (2 trip detection logic).

 Leave a Reply