Random turbo drop-out

[Doug999]

Hi,

My apologies if this is a topic that has already been covered. The car is a 2007 fabia 1.9tdi.

Engine management light came on and the turbo dropped out whilst on a long journey. Didn't appear to be in limp mode as I could still do 70,it just took ages to get to it! Once the engine was stopped then restarted, light was off and turbo worked fine... Until next long journey where the same thing occurred. Eventually i was having loss of turbo on short journeys too. OBD scan shows the following fault codes:P0236 Turbocharger Boost Sensor A Circuit Range/Performance;P0234 Engine Turbocharger/Supercharger Overboost Condition;P0113 Intake Air Temperature Circuit High Input;P0101 Mass or Volume Air Flow Circuit Range/Performance Problem.

Car has been to the garage - no mechanical fault found - they couldn't explain these codes. Private mechanic has removed and cleaned turbo and egr. Turbo vanes are moving freely. Air mass meter has been replaced as has the vaccuum control box thing for the turbo. Yet still the problem persists. Turbo works sometimes but then drops out and will not kick in again until the engine is stopped, rested and started again. Other than that car drives well, not jerky, no bad exaust (occasional black smoke on heavy acceleration). Car has been regularly serviced but does do mostly short journeys. My thinking is still bad turbo but mechanically it seems to be ok. Is there a sensor i am missing or is there a fault I've not considered. Your input is greatly appreciated.

[Doug999]

Extra symptoms to the above... Slightly. Higher than normal idle speeds and a humming noise from the engine bay drivers side when engine is turned off - like a vaccuum discharge.

Thanks

[R1chard]

Sounds like a faulty map sensor?