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Discussion Starter · #1 ·
Hi all,

2003, AWM, 1.8T, automatic.

P0299, P0563 for Engine
P1751 for Transmission

Check engine comes on in 4-5 days after I clear the codes.

The boost reaches 8-9 psi per the boost gauge I installed.

VCDS shows both engine and transmission voltage as 14-14.9.

The car is sluggish at lower rpms but picks up when flooring the gas pedal.

Where should I start?
Thanks.




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Scan for requested vs actual boost. I think you can graph it. If boost is slow to build, it will throw the code. An internal leak in the DV can cause slow boost, a loose/bad wastegate, timing off by 1 tooth, plugged cat or exhaust, bad O2...
 

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Discussion Starter · #3 ·
Scan for requested vs actual boost. I think you can graph it. If boost is slow to build, it will throw the code. An internal leak in the DV can cause slow boost, a loose/bad wastegate, timing off by 1 tooth, plugged cat or exhaust, bad O2...
Could you tell me how I can do it? Never tried it before.


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Sorry, I don't know as I no longer have my 1.8T. I've just seen them posted on here before. Since you mentioned the car is sluggish at lower rpm, it's the best way to see boost build.
 
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P0563 for Engine
P1751 for Transmission

It appears that you have an intermittent fault in the alternator voltage regulator.
This could damage any any electric components in the car, if it doesn't go over 14.9 volts, it is only likely to damage the battery.

I would check with a volt meter, while gradually increasing revs to about 4k or stop if you get a reading above 14 volts.
Being intermittent, you might need to connect the meter so that you can monitor while driving.
If you get a reading above 14 volts, you need to replace the regulator.
 

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If it is the voltage regulator, it is easy to change out once you get the alternator off. Fairly cheap, too.
 
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