1.8t low boost

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JogiahMk4
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Car Make: VW
Car Model: Mk4 GTi (110kw)

1.8t low boost

Post by JogiahMk4 »

My agu isn't boosting higher than 0.3 bar , I pressure tested, found a boost leak , sorted it out but now the car still won't boost above 0.3 bar , I disconnected the boost reference hose to the n75, went for a small drive and i was getting 0.6 bar. The only faults I'm getting when scanning with vagcom is p1559 and p1565 which are throttle body fault in basic settings and lower stop limit not reached . This may be because I tried to do a TBA with the car started , I can't perform one with only ignition on as VCDS doesn't communicate with the ecu with only ignition on , car had to be started.

I checked the ohms on the pins of the n75 and they were within range . I also logged the n75 duty cycle and it's almost always at 0, rises to 5 percent at wide open throttle in certain cases but no more than this . Seems like the ecu is limiting boost but I'm not sure why. Would the throttle body codes cause this ?
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PapaJo
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Re: 1.8t low boost

Post by PapaJo »

It is likely that the tb errors might play a part there. Get those errors fixed/cleared and then work from there. Do a proper tb calibration to ensure tb feedback is correct.
JogiahMk4
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Posts: 42
Registered for: 3 years 3 months
Car Make: VW
Car Model: Mk4 GTi (110kw)

Re: 1.8t low boost

Post by JogiahMk4 »

Thanks for the response Is there any way to do this without vcds ? Vcds doesn't communicate with the ecu unless the car is started which is preventing me from doing a TB callibration or any idea why vcds doesn't communicate with the ecu with the key turned to the on position.
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