540d Drivetrain issues

  • Hello again


    Not long ago I fixed my DPF issue.

    Now I have following DTC;
    244B00 - Charging pressure control, low-pressure stage: Charging pressure too high

    This code comes every time the same. When giving the car full beans and changing gear approx. 180km/h. This fault occurs and car goes to limp mode.

    With ISTA, every test related to turbo and intake stuff PASSED. One thing seemed odd. I don't recall the test name, but it checks the charging pressure with different RPMS and moves the turbo flaps around?
    It kept RPM @ 3000, and the car juddered a lot at the same time. Should this be part of the test?
    Also in Live Data this seems a bit odd?
    760: Variable turb. geometry controller actual value low pressure: 74.88%
    761: Variable turb. geometry controller setpoint value low pressure: -1.11%

    762: Variable turb. geometry controller actual value high pressure: 87.83%

    763: Variable turb. geometry controller setpoint value high pressure: 0.76%



    305600 - Oxygen sensor after catalytic converter, plausibility: Lambda value too low in coasting overrun mode.

    This fault does not trigger anything. And "present" value of the code is always "no".
    After deleting fault memory I checked live data which said the following;
    Ox sens. before cat Air ratio: 0.25
    Ox sens. after cat Air ratio: 4.08
    This was a brief fast check at idle.


    22B100 - Diesel particulate filter: Efficiency too low.
    This fault comes back every time when I delete fault memory.
    Differential pressure is ok, DPF regeneration is working. This code does not trigger drivetrain fail.

    Any help? The car has been stage 1 tuned. It smokes a tiny bit at full throttle under certain conditions.
    I have not tried accelerating to 180km/h + before the tune. So hard to say is the boost problem from the remap.