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Discussion Starter · #1 ·
now my lead is finally here,ive just scanned my van and im getting a fault reading as the charge pressure control which if none of my pipes are leaking its the n75,ive read enough on the forum to see that its more than likely my solenoid on the n75.or am i wrong in swapping out my n75 valve?

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

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now my lead is finally here,ive just scanned my van and im getting a fault reading as the charge pressure control which if none of my pipes are leaking its the n75,ive read enough on the forum to see that its more than likely my solenoid on the n75.or am i wrong in swapping out my n75 valve?

17965/P1557/005463 - Charge Pressure Control: Positive Deviation
I have the exact same problem, I have narrowed it down to the fuel filter, looks like it has never ever been changed even though I have the paperwork for a full service from August :/ just bought replacement silicone hoses and a N75 to replace them just incase it is not the fuel filter
 

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where did you buy your n75 from mate?
i already have silicon hoses to change T:
I got mine from TMS, they were really helpful with me, and actually took the valve off to get the code for me, I have the more expensive £135 one but the others were around £35/40.

I am going to change all the pipework and the N75 once I get a replacement cap for the top of my never been changed before fuel filter which I snapped off and cover all bases, hopefully will cure my problem.
 

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Discussion Starter · #9 ·
Just changed my little pipes out this morning,didn't take long,only a couple were a mare but over all an easy job and worth doing.
 

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This is what ross tech says

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

Possible Symptoms
## Reduced power output
## Limp mode

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

## Solenoid Valve for Boost Pressure Control (N75) defective

Possible Solutions
## Check Hoses/Pipes to/between Components
## Check Solenoid Valve for Boost Pressure Control (N75)
## Check / Clean / Replace Charge Pressure Control ## Check / Clean mechanism for variable nozzles
 

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Discussion Starter · #14 ·
ive changed all the air pipes,ive got another n75 valve on the way,i did see what ross tech said,im hoping its the n75 valve :D
 

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I have the same code on my 2.5 tdi velle.The hoses have all been changed,the waste gate moves freely.The only quandary I have is that when checking the feed and earth to n75 valve with the ignition on I have 12v at pin 1 but rather than an earth on pin 2 I have 3.3v? When the engine is running does this change to a switched earth? With no power to the solenoid you can blow into the top port and feel it blowing out of both bottom ports so if I had a wiring issue to the n75 surely these ports would be permanently letting pressure through to the waste gate and I'd have under boost rather than over?
 

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I was receiving the same 3.3 volts
12 v from pin one to ground 3.3 volts from pin 2 to ground and 8.7 volts between the pins.
I used a boost gauge on the turbo it was producing about 15 pounds max boost without the n75 valve, then it would go into overboost mode about 9 10 psi until reset with ignition.
With the n75 valve replaced I was only getting 6 psi boost
I replaced the n75 valve with a new one from vw ( that is a mother storey here on the west coast of Canada ) but now enjoy an easy 14 psi boost. And a great running t4 acv engine.
 
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