Please Help With A Unique P1556 Code - VW Vortex

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biacofano B Okay, this problem may need the Dr.House of tdi knowledge. I bought my 2002 Jetta TDI about 2 months ago. When I bought it the engine light was on and it was a P1556 problem. From there I took apart the intake and replaced it with a new one, and replaced all the gaskets with new ones when I put it back together. The intake was clogged pretty good, but still no boost from the turbo. From there I replaced the N75 valve with a new one, and replaced all the vacuum lines, as well as a new bosch fuel filter(air filter is clean). It seemed as if that fixed the problem but the code would still reoccur and the boost would only last a few seconds then cut out. I was never able to go completely down a freeway onrap without it cutting power. I restarted the engine and it would seem to come back for a minute, but then I havent felt boost after the first few time doing this. In other words, I definitely do not feel any boost at all now. Finally, I replaced the actuator with a new one. I also replaced the MAF with a new bosch one. Then, I realized I was probably doing the diagnostics in reverse order. First I should see if there is vacuum, and why it is not reaching the turbo actuator. I made my way to the hard line from the brake booster which has a type of T which I beleive supplies vacuum to the system. However, with the engine running (at idle) there is no air flow comming from the T that is inline of the brake booster line that comes out to the side of engine. There is no obvious leak near the brake booster, and my brakes operate normally. Shouldn't this location offer a constant vacuum? Also, any other ideas on what I could test next to get my boost going? I appreciate any help you guys can offer. I have been up and down every forum, website, and search engine and have found nothing similiar to my issue. I have only a simple scanner that allows me to read and erase codes. #1 · Dec 2, 2009 Okay, this problem may need the Dr.House of tdi knowledge. I bought my 2002 Jetta TDI about 2 months ago. When I bought it the engine light was on and it was a P1556 problem. From there I took apart the intake and replaced it with a new one, and replaced all the gaskets with new ones when I put it back together. The intake was clogged pretty good, but still no boost from the turbo. From there I replaced the N75 valve with a new one, and replaced all the vacuum lines, as well as a new bosch fuel filter(air filter is clean). It seemed as if that fixed the problem but the code would still reoccur and the boost would only last a few seconds then cut out. I was never able to go completely down a freeway onrap without it cutting power. I restarted the engine and it would seem to come back for a minute, but then I havent felt boost after the first few time doing this. In other words, I definitely do not feel any boost at all now. Finally, I replaced the actuator with a new one. I also replaced the MAF with a new bosch one. Then, I realized I was probably doing the diagnostics in reverse order. First I should see if there is vacuum, and why it is not reaching the turbo actuator. I made my way to the hard line from the brake booster which has a type of T which I beleive supplies vacuum to the system. However, with the engine running (at idle) there is no air flow comming from the T that is inline of the brake booster line that comes out to the side of engine. There is no obvious leak near the brake booster, and my brakes operate normally. Shouldn't this location offer a constant vacuum? Also, any other ideas on what I could test next to get my boost going? I appreciate any help you guys can offer. I have been up and down every forum, website, and search engine and have found nothing similiar to my issue. I have only a simple scanner that allows me to read and erase codes. See less See more Sort by Oldest first Oldest first Newest first Most reactions #2 · Dec 2, 2009 There wouldn't be air coming out of the T-connector: it should suck air in. If you have power brakes, then there's vacuum in the system. Have you verified that the VNT mechanism is working properly? The best way to check it is to put the car on ramps, remove the skid pan, and use an open end wrench to try to move the actuator--either 13mm or 14mm. It should move fairly easily with no binding. http://i176.photobucket.com/al...d.jpg #3 · Dec 4, 2009 I replaced the old actuator with a new one since it was binding a little bit(it still moved up and down but I wanted to be safe). I noticed with the actuator off the rod that comes out of the turbo was able to be moved back and forth very easily so I believe the vanes must be in good condition. Also I noticed that when I floor the gas pedal on the freeway the rpms go up to about 4000 but then drop suddenly to about 3750 and are slow to go back up. Is this the fuel being cut from limp mode? To summarize I replace: n75, actuator, vacuum lines, MAF, intake manifold. Insert Quotes Post Reply

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