I've searched around and am still having trouble with limp mode on my 1999 Beetle TDI. I've been having this issue for a few months now. It fist started ONLY when in 5th gear, cruise control @ about 70 MPH on a steady hill. I'd just turn the car off and restart it on the downhill and problem solved. The 2nd time it would happen during my commute it would throw a CEL with a code of P1550 - Charge Pressure Control Deviation - Intermittant.
Here is a list of the things I've done to date:
1) Replaced all the vacuum lines.
2) Swapped the N75 Valve with the EGR. No change. (I never swapped them back, could this be an issue?)
3) Unplugged the MAF, the car ran horribly, so I plugged it back in
4) Sprayed the VNT rod and actuator with PB Blaster and went for a hard drive.
5) Replaced the VNT Actuator with a new one. The old one was bad because when hooked up to a vacuum pump the rod didnt move until about 10 and made a popping sound while the new one moves at 3.
Today with the new actuator installed the problem (limp mode) happend in third gear under load, the problem got worse with the new actuator! I adjusted the new actuator rod length to that of the old one and when I had it off of the turbo, I was able to move the turbo VNT rod with my fingertip. It moved very easily.
6) I ran VAG-COM and went to measuring blocks group 11. I was told that the graph lines should stay realitively close together but when I gave throttle they didn't.
Does this mean that the turbo vanes are'nt sticking? Is it a bad N75? Any help or suggestions would be appreciated!
Here is a list of the things I've done to date:
1) Replaced all the vacuum lines.
2) Swapped the N75 Valve with the EGR. No change. (I never swapped them back, could this be an issue?)
3) Unplugged the MAF, the car ran horribly, so I plugged it back in
4) Sprayed the VNT rod and actuator with PB Blaster and went for a hard drive.
5) Replaced the VNT Actuator with a new one. The old one was bad because when hooked up to a vacuum pump the rod didnt move until about 10 and made a popping sound while the new one moves at 3.
Today with the new actuator installed the problem (limp mode) happend in third gear under load, the problem got worse with the new actuator! I adjusted the new actuator rod length to that of the old one and when I had it off of the turbo, I was able to move the turbo VNT rod with my fingertip. It moved very easily.
6) I ran VAG-COM and went to measuring blocks group 11. I was told that the graph lines should stay realitively close together but when I gave throttle they didn't.
Does this mean that the turbo vanes are'nt sticking? Is it a bad N75? Any help or suggestions would be appreciated!