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Discussion Starter #1
i have a golf 52 plate gt tdi 130 with remap to 170.
had the turbo reconed 2000 miles ago and has been running fine.
this week it has started going into limp mode all the time.
i have checked all the intercooler pipes and replaced a few that were worn and had movement in them.
i have replaced the turbo pressure valve aswell.
it runs better now but only if u start in 1st gear and give it death right through the gears. but say i was driving in 3rd and under 2000 revs then slowly started to accelerate the turbo would start to boost then after a few seconds would put the car back into limp mode.
i got the car plugged into a comp and it came back with with a code saying turbo pressure switch intermittent negative deviation.
i have checked all vac and boost hoses with no leaks to be found!

so any 1 have n e ideas on what could be wrong?? its driving me nuts

thanks
 

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I assume turbo pressure valve is the N75 solenoid? If you're sure the vac lines and N75 are fine it could be a bad wire to the N75, bad vanes, bad boost sensor.

Details on the exact error code number and readings of the MAF, boost requested vs. boost actual would help. Although you don't say it's fuel related, also check the fuel filter and fuel injection quantity.
 

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Discussion Starter #3
ok thanks.

is there n e way of testing these other that might be wrong?
yes that was the n75 solenoid i replaced.
i assume i need it plugged into the comp again for the readings of the maf and boost requested vs delivered figures.
thanks
 

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Use the VCDS because it's the most accurate way of testing the sensors, wiring, etc. If the wiring is bad but the sensor is good it will be reflected in the reading.
 

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VCDS is a computer cable and diagnostic software from ross tech. http://www.ross-tech.com/Merchant2/merchant.mvc?Screen=CTGY&Category_Code=VAGCOM There may be a similar cable in the UK. Don't bother with the generic ones from ebay unless you just need it for something simple. In your case you want to do more troubleshooting so get a genuine cable. If your car is obd2 and not CAN BUS you need the KII-USB or Key-COM cable. One is USB hte other is serial connector.
 
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