17965/P1557/005463 Error on VW 1.9 TDi

[infinity23]

Hi all,

I bought a TDi used 3 weeks ago.

It goes into some sort of limp mode inconsistently, doesn't go more than 30 or 40, and during the 10 second process it has a guzzling noise and black smoke heavily coming out of the back.

TDi seems to have power, whistling sounds good, and as I mentioned this only happens maybe once a day more when car isn't warm yet.

Plugged vagcom, which I managed to borrow for an hour from a friend.




17965/P1557/005463 - Charge Pressure Control: Positive Deviation

Possible Symptoms

1. Reduced power output
2. Limp mode

Possible Causes

1. Boost Pressure too High
2. Hoses/Pipes incorrect connected, disconnected, blocked or leaking
3. Charger Pressure Control defective ## VNT (variable nozzle turbo): nozzles stuck

1. Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions

1. Check Hoses/Pipes to/between Components
2. Check Solenoid Valve for Boost Pressure Control (N75)
3. Check / Clean / Replace Charge Pressure Control ## Check / Clean mechanism for variable nozzles

I have read up quite a bit and know to try and change the N75, or check the boost pipe. im not too car techy so did the checks I could and all seemed fine.

Called a "VW" specialist, and he advised straight away to change the turbo. 500 for turbo 200 for labour.

I cant really afford it unless its a worse case scenario,

Was looking to see if anyone here could advise? I have it booked into a mechanics on Monday for a free opinion, but am curious whether it may just be an N75 issue or something less major than needing to change the whole turbo?

Your views appericiated,

Thanks in advance.

[spats]

before thinking busted turbo I would be checking all the vac hoses (theres a number of them) and making sure theres no problems aparent there.

Next get under the car and when the turbo is cold you can reach up and find the end of the turbo actuator arm. This is the device which opens and closes the vanes on the turbo. You should be able to pull the arm down and feel resitance from the actuator. It should move smoothly and need a fair bit of pressure to move. If you cant move it then its either the actuator has seized (happened to mine) or the vanes are stuck.

If the vanes are stuck you can use mr muscle oven cleaner by inserting a tube down the egr pipe (after taking the egr valve off) and soaking the vanes with cleaner. This has proven to work in most cases. Search for vnt vanes and mr muscle and there should be how2's and videos showing how to do it.

Theres also 2 valves on the back of the fire wall, ones the n75 which works the turbo actuator, the other is the valve used for the anti shudder and egr system. You can temporally swap these round to see if the n75 is duff. I forget the specifics, as i didnt bother and just tried another n75 that was known as good.

[infinity23]

Hi Spats,

Thank you very much for such detailed instructions.

I am at work now, so will attempt to do this tonight when I get in.

I live in central London and my car is parked on what feels like the busiest road in the UK so I will do my best.

Sounds like something I should be capable of doing.

I agree to make these checks before I go with busted turbo. Im sure a busted turbo would be much worse than what is currently happening now. It drives beautiful most of the time with great power at most times. Then again I don't know anything about cars.

Will post an update.

Best

[infinity23]

Sadly I couldn't make it last night, got home really late.

Will try again tonight.

These checks sounds really advanced so I hope I can pull them off :S

Thanks again