Check engine light came on after oil change

We just bought an 02 1.8T Jetta with 90K, drove it for 3 weeks no problems, got an oil change from the VW dealership and on the way home the check engine light came on. Phoned as soon as we got home and they said we could bring it in to get it diagnosed but if it wasn't related to the oil change we would be charged the fee ($100), if it was related it would not be charged of course. So I decided not to take the chance and I bought a code reader with a shareware version of VAG-COM. I got 3 codes out of it -

P0332 (knock sensor signal too low - intermittent)
P1297 (Connection turbocharger - throttle valve pressure hose (Check your DV hoses) )
P1127 Intermittent - 17535 P1127 Long Term Fuel Trim mult.,Bank1 System too Rich

I had to look up the last 2 online cuz shareware only gives me one code so I hope they're right. So my question, could any of these be caused during the process of doing an oil change or was it just coincidence? Also, are these easy to fix by myself or do I have to bring it in? Thanks for any help.

check the hose coming from valve cover and look for a ripp or tear.

there is also a vacum line that goe's to the DV look at it make sure it's not broken.

your knock sensor DTC is for Knock sensor 2 this is located between cylinders 3,4 this would be related to the first two faults. the code read botton to top so the first code was your.
fuel trim then charge air preasur then your knock.

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thanks for this, i checked again last night and only got two codes this time (knock sensor and turbocharger pressure) so I cleared them, 10 seconds later they came back, cleared them again, turned car off, checked the hoses, removed larger hose at turbo end (can't figure out the clip on the smaller hose and I didn't want to screw something up), couldn't find a (visible) tear in either DV hoses, put large hose back on, tightened it really well, started car, no codes, took it for a rip, still no codes. So, so far so good..we shall see I guess...[/quote]

great to hear that nice work.

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so much for that, codes are back and the car seems to be making quite the "whooshing" sound when you step on the gas (only in drive tho). I can't tell if the sound is suction or blowing but I know it's coming from the passenger side of the engine. I know the turbo should spool up but I think the sound is getting louder. Having the 96K service done this weekend so hopefully they will find out what it is. Any ideas you might have would be appreciated so I'm not going in totally blind. Thanks.

there is you cooler hose that could have come off.

what codes did you have come back?

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haven't scanned them again yet, just presumed they were the same ones, they came back the next day but we've been on vacation for a while so I couldn't scan. I'll scan when I get home tonight and let you know for sure

this is what I got this time....

5 Faults Found:
17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)
P1297 - 35-00 - -
16716 - Knock Sensor 2 (G66): Signal Too Low
P0332 - 35-00
18613 - Performance Malfunction in Cooling System
P2181 - 35-10
17535 - Intermittent - 17535 P1127 Long Term Fuel Trim mult.,Bank1 System too Rich
P1127 - 35-10
16683 - Boost Pressure Regulation: Control Range Not Reached
P0299 - 35-00

The cooling one I think (and hope) is related to the coolant needing to be changed as I've already been told.

alright cooling p2181 is a t-stat.
trust me just change it out.
all other there is a boost leak some where.

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So we got it checked out this weekend and there was a hose off for the turbo, I got the guy to show me where it was since I had spent a half hour or better looking for it myself and it was at the back of the engine on the passenger side down low behind a heat shroud of some sort. He said he had to get at it from below which explains why I couldn't see it since I can't fit under there without jackin er up, which I will do next time.

Apparently the previous owners had the wrong coolant put in for the engine which, according to the mech, could gel up in the lines and cause extensive damage. Between that and a failing coolant sensor I got the coolant fault code. Flushed the system and put in new coolant and sensor.

And the knock sensor is failing...I think that one's pretty easy to change out myself so I'll spend the 90 bucks on the part and save on the labour.

So that's the saga...now the car goes like snot again and hopefully the gas mileage comes out of the shitter. Thanks for all your help on this Volkshaus, it has been very informative.