2002 TDI Jetta Boost issue

Little update about my car! This weekend I went back to the junk yard and got some wiring harnesses and a ACV, brake vacuum pump. Replaced them both on the car and noticed a hugh difference in the way the car drove. Put the new MAF sensor in and car was almost back to normal. Drove it about 5 miles and P0120 light came back on. The MAF sensor from Bosch is brand new. So going to put back one of the other ones i have in and see today what happens. Has anyone had brand new MAF sensors not work. Or is there something else to check that could be pulling the code. I do not have the any other lights coming on so that's good news.... Any and all comments and help have been awesome! Thanks to all for the advice..... David

Here is the latest. Cleaned my new Bosch MAF sensor when i got home last night. Drove it around the block and right back into limp mode between 2 and 3rd gear. Pulled P0120 code so I unplugged it and the car runs allot better but not 100%. Drove it to work this morning and still doing the same. After driving about 15 minutes and car gets to temp light comes back and I pulled over and ran scan again P0102. Unplugged and go to work. Got a new Bosch MAF coming from Amazon. Does anyone know if a P0102 can be anything besides MAF? Any and all help and advice is appreciated. Really don't want to take this car into the shop for them to find something stupid..... TDI-ier in Jax

Wiring. The drive without MAF test is not conclusive for the MAF itself. Early forum days there were endless discussions to pack the connector with di-lectric grease (silicone), which is actually counter intuitive, but it often worked, suspect because the application resulted in cleaner connects. But as our cars get older, we're seeing loads of errors from wiring, many are really small.

BobnOH said:

Wiring. The drive without MAF test is not conclusive for the MAF itself. Early forum days there were endless discussions to pack the connector with di-lectric grease (silicone), which is actually counter intuitive, but it often worked, suspect because the application resulted in cleaner connects. But as our cars get older, we're seeing loads of errors from wiring, many are really small.

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Here is what happened yesterday. I got one more MAF Bosch sensor from Amazon. Put it in and got no codes where i was getting a P0102 error last few days. Still in limp mode and MAF connected. Un plugged and the same still in limp mode. Weird! Checked the connector and attached a new one i got from the junk yard over last weekend. The one that was on there was old and cracked. So new connector new MAF and still limping.... not sure I am really scratching my head on this one. I just want my turbo kicking again! Love that little car don;t want to get ride of it now.....

Boost hose connections are all tight. Down by the IC can come loose.