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Vida can show 5 Items in its graph view, or 10 items on the data view. So i prefer the data view. You can get more done in a shorter time. But in order to be able to review it we need to use screen recorder like Screenpresso (download from here) . You also need to remeber that you need to give the data context, something like throttle position and RPM .
This instance it was is a 2010 2.4 D5 engine.
The customer in question here had ECM-P029900 – Underboost condition and the car would go into limp mode.
The fault code states “Charge pressure is below the permitted parameter” and that the probable causes are :-
■ Air leaks in the induction system.
■ Damaged vacuum hoses.
■ Faulty air temperature sensor inlet.
■ Damaged pressure servo for the turbocharger (TC) control valve A (wastegate).
■ Damaged turbocharger (TC) control valve A (wastegate).
■ Damaged turbocharger (TC) control valve B (bypass).
■ Damaged passive by-pass valve for EGR.
■ The EGR-valve has jammed in open position.
■ Damaged turbo charger (TC).
■ Blocked exhaust system.
Its always seemed to me that volvo list the faults in “likely” to “unlikely” , with blocked exhaust being very unlikely and air leak being very very likely.
So I set about checking live data from the car. The IAT sensor seems sensible, the EGR was not stuck open, the turbo seems to boost well and try to hit comamnded boost (but mostly fails). The boost pressure sensosrs and barmotic pressure were always very very close as they should be.
However I noticed that the MAF air temp and TMAP (on the intercooler) were always quite far apart. When the car had been stood overnight the TMAP registerred ambient temp but the maf was about 15’c higher.
When the car was started the MAF reading was quite a bit lower than the expected 55kg/hr.
In this long boring video if you skip to 2:40 you can see some good boost, but not long after it is in limp……and then at 6:20 the driver give it some beans.
The boost is low and cant quite follow the demand and the maf vallue is unfeasably low. 250kg/hr equiates to about 85hp. I dont think the 2.4 d5 can produce that little HP hahaha.
So the question is now….is the MAF faulty or is the Air being sucked in through a leak in the intake.
My money is on a leak.