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Thread: AUDI A6 2.7L Petrol Allroad - engine fails to rev up under load

  1. Default AUDI A6 2.7L Petrol Allroad - engine fails to rev up under load

    Hi everyone,
    my C5 A6 2001 2.7L petrol manual Allroad has developed an issue where it fails to rev (or very slow to rev up) when under load ie.going up a steep hill etc.
    It seems to start limiting itself at around 2,500 - 3,000 RPM
    The engine will rev up normally when at rest.
    I have reset the engine fault codes and these are the ones that keep coming up:

    • 17840 - secondary air injection solenoid valve (N112) opencircuit: P1432


    • 17865 - exhaust gastemp sensor 2 open or short (G236) TO Plus: P1457


    • 17965 - charge pressure control: positive deviation (P1557):P1557


    • 17521 - oxygen (lambda) sensor B1 S1: int resistance toohigh:P1113


    • 17539 - oxygen (lambda) sensor B2 S1: int resistance toohigh: P1131


    • 16487 mass air flow sensor (G70) signal too high: P0103


    • 17535 fuel trim bank 1 (mult) system too rich: P1127


    • 17537 fuel trim bank 2 (mult) system too rich: P1129

    Nothing obviously amiss under the bonnet.
    So just wondering if anyone has had this, or a similar defect before and any suggestions as to the best course of action.
    Any help appreciated.
    Thanks in advance.

  2. #2

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    Quote Originally Posted by AllroadSR View Post
    Hi everyone,
    my C5 A6 2001 2.7L petrol manual Allroad has developed an issue where it fails to rev (or very slow to rev up) when under load ie.going up a steep hill etc.
    It seems to start limiting itself at around 2,500 - 3,000 RPM
    The engine will rev up normally when at rest.
    I have reset the engine fault codes and these are the ones that keep coming up:

    • 17840 - secondary air injection solenoid valve (N112) opencircuit: P1432


    • 17865 - exhaust gastemp sensor 2 open or short (G236) TO Plus: P1457


    • 17965 - charge pressure control: positive deviation (P1557):P1557


    • 17521 - oxygen (lambda) sensor B1 S1: int resistance toohigh:P1113


    • 17539 - oxygen (lambda) sensor B2 S1: int resistance toohigh: P1131


    • 16487 mass air flow sensor (G70) signal too high: P0103


    • 17535 fuel trim bank 1 (mult) system too rich: P1127


    • 17537 fuel trim bank 2 (mult) system too rich: P1129

    Nothing obviously amiss under the bonnet.
    So just wondering if anyone has had this, or a similar defect before and any suggestions as to the best course of action.
    Any help appreciated.
    Thanks in advance.
    Sad to say there are more than a few things happening under the bonnet. Potentially your two major engine protection sensors (O2 & EGR) are both duff so the ECU will revise the power down to protect the engine. The symptoms you described can indicate that the car is in limp mode where the boost pressure is limited to ~5 psi. On occasion one fault can initiate the appearance of other faults that may not exist if the prime fault is resolved.

    You have access to a code reader so are you mechanically inclined and have tools?

    I'd probably start with checking / cleaning all the plugs and connectors for the EGR and O2 sensors. clear and check codes. Probably no fix but worth trying. Next I'd change out the lambda and EGR sensors and try again. IF that resolves the EGR and O2 codes then you can see whats left.

    In most cases it's a lucky strike to make any attempt to diagnose via a forum. If you don't have a VAG knowledgeable friend I'd really think about using a mechanic. Probably an accountant too as the parts aren't that cheap if you need to fix that entire list. Good luck.
    B5 RS4 : Lightly modified -- C5 2.7 allroad -- B5 A4 1.8 quattro 132 Kw -- UNIMOG 404 TLF8

  3. The Following User Says Thank You to IchBautAuto For This Useful Post:

    AllroadSR (January 21st, 2019)

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