Fault p1556 p1144 17552 on a 2003 passat.

It's a turbo problem of sorts. Have a look on the following link which will give you access to more information:

passat eror code 17965 Google Search

To be quite honest, there's nobody on Fixya who will be able to give you a definitive answer. Turbos can suffer from a number of faults and those faults can sometimes be quite difficult to track down.

Here's a link to Ebay:
passat turbo

It may be worth your while actually contacting a turbo specialist and asking their opinion. What you don't want to do is fit part after part in hope of curing the problem. Your first course of action should be to ask a turbo specialist or good workshop. Yes, it may mean paying for somebody to check things out for you, but it really does save money and bother in the long run.

Need to scan ECM for faults.

hi mate, my 55 plate passat did the same before major problems happened. first turbo went then the oil pressure light came on and the car went into limp mode. before its too late for you and a costly bill can you do the following.
check if your car has a recall for the injector problems which vw are replacing under warenty.
second thing the guy who repaired my turbo told me that these cares have a major fault which caused the turbo to go. the fault is the oil pump failure you must adress this issue as you can get a lot of info on the discussion forms.
my car started with the same problem as you have described the pd engines have a design fault with the oil pump and shaft. this is common causing your turbo to go then the car will start showing oil pressure low please stop engine. educate your self via the forms and act quickly befor you end up with massive bills.
i hope this has helped. trust me vw know about this design fault.you need to change your chain driven oil pump to the new gear driven system which vw have modified. all vag cars have the same problems be it audi skoda vw . my car had the same problem as you have said .started off with emissions then turbo failed thats when i started to investigate this problem . the pd engines was designed by some rookie at vw.

You may have lost programming to the body control module, contact the local VW dealer to scan the system for faults.

I would assume some of the emission component failed and you have to take it to a workshop.

99% of the time when the emission warning light is turned on there is no symptom u can feel, however there is a fault present present in the memory of the powertrain control module (known as the PCM), have the cars OBD2 electronic engine control system tested to find out what the fault code is, there are over 200 poss codes.

perhaps it is the knock sensor? situated below the intake manifold.

Your EGR Valve is clogged and has to be changed. I have tried removing, cleaning and replacing it, this only lasts from one hour to one week.

The fault code 'P3103 V157 - Intake Manifold Flap' comes up on the diagnostics, and if you look in your fuse box (next to the battery) you will see a blown 10amp fuse. This is a sure sign that your EGR (or Intake Manifold Flap) is stuck.

This unit costs about £235 - £250.
Good luck mate