A6 2.0TDI p2002 fault code confusion

[Jamdodge15]

Hey guys, having some issues with my car. Have taken it to a couple of different places now and they have diagnosed different issues with the car.
Firstly car was a bit jittery under acceleration then would throw up the flashing ignition coil light. When read with my wee old reader it would show - P0237
Turbocharger/Super- charger Boost Sens- or A Circuit Low

This would trigger limp mode. Then a little while later then engine management light would come on with the p2002 code - Diesel Particulate Filter Efficiency Below Threshold Bank 1.

The car has about 78k on the clock and has been well maintained and serviced. First mechanic said that the egr cooler was blocked and would require a full strip down at a massive cost. Second mechanic has diagnosed an air flow sensor fault.

Which one is right? Is it possible the faulty flow sensor could trigger the p2002 code? Any insights appreciated thanks

[dean warren]

What model and year is it? If its the ultra i suspect the expensive route is unfortunately correct


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[Jamdodge15]

Yes it is indeed the 2.0 TDI ultra. I should also add that the flashing glow plug is an intermittent fault. When not triggering the fault, the car performs well through the entire rev range.

[gareth23]

When I had the P2002 error on my A4 it always drove normally, it never went into limp mode and regens always worked. Since replacing the DPF cooler is a huge/expensive job it might be worth speaking to the second mechanic to get more info on what he thinks. It could be one of the pressure sensors has failed.

[swalker]

A friend in work has the 2002 code issue on his A4 - EGR cooler as mentioned - car still runs ok and the fix comes in at about 1K. there is a few posts on here about it.
To me the flashing glow plug and loss of power is a boost thing and could be something different or if you are unlucky a second fault.
A VAG specific reader is a must. My TOPDON TopScan is not - it will cover Audi and scans all the 12 or so different control modules, but didn't pick up on a failed glow plug, which must have a VAG specific code as my OBDeleven did.
good luck

edit:- the 2002 code could be an effect of the loss of power as it is an insufficient flow fault, if the power is shut down the flow wont be there?