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Discussion Starter · #1 ·
Got a (rare for me) CEL this morning - maybe only the 2nd or 3rd in 46K miles so its got me spooked. Here's what my VAG-COM found:
  • 16683 - Boost Pressure Regulation. Control Range Not Reached.
    P0299-002 - Lower Limit Exceeded- Intermittent.
Got this after relatively hard acceleration going uphill with the a/c on. What happened here? TIA.
 

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PassatWorld Staff
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It means that you are not getting as much boost as the ECU is requesting. This, as Rechts said, could be your N75. It could also be a small boost leak somewhere, esp. vacuum lines. It could be several other hoses, too. Or it could be the wastegate going bad.

At 46K on a '03, it's most likely (and easist to fix) that you have vac lines going bad - if you haven't already replaced them, do it with 3.5mm hose from www.hosetechniques.com
 

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Discussion Starter · #4 ·
Thanks y'all. I'll clear the code and see if it comes up again. Probably home in on the vacuum lines for now.
Sigh ... anything "thing" to do :roll:
 

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I had the same thing happen a while back. I cleared the code and have not seen it again. Hope that same is true for you.

I think the boost level the ECU is looking for under hard accelleration with the AC on is not reachable in certin situations and it is not a reflection of the system having a problem. :weirdo:
 

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PassatWorld Staff
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RAWERW said:
...I think the boost level the ECU is looking for under hard accelleration with the AC on is not reachable in certin situations and it is not a reflection of the system having a problem. :weirdo:
This hadn't occured to me, but upon reflection and looking back at some of the weird temporary CEL's I've gotten, I think it is the most likely explanation. Thanks, Randy! :thumbup: :thumbup: See you at the GTG?
 

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I get odd things all the time. Right now I keep getting the following:

1st code - MAF reading below lower limit.
2nd code - Oxygen sensor - 2nd bank - below limit, resistance too high.

All of this is a product of a bad MAF, the first code is right, but not because the engine is starved for air, but because I have a crapy MAF. The dealer is fighting me on it. - Mod the intake and they tell you that is the reason, never mind the KNOWN MAF issues with the 1.8t. I have swapped it our with a good one and no code...so you decide.

Anyway back to the point - so the other code is a result of the MAF reading incorrectly. The rest of the sensors process bad information and throw more codes. The car runs fine, but the codes keep showing up.

One bad reading at the top of the line will result in more as you move throught the system. I alwys try to fix the top of the system and usually the rest falls in line.

Rusty - I will be there. Two sets of tires and a helmet :thumbup: what else do you need.
 

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I had my mechanic tackle a leaky gasket on my car and replace the cct gasket. Also, had the jet pump replaced.

now, I want to tackle my second problem. I have low boost and it appears the culpret is the n75 valve... I'm surprised how expensive this part is... ecs has their racing one available one for 75$ but i'm wondering what the useful life is of this item?

Otherwise, I might go with the geniune product by VW.
 

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Wants to be TheFlipperGray
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I would buy the OEM one..

The "race" N75 have had mixed reviews: some see an extra bump in performance; some over boost and spike right into limp mode. I don't know what engine code you have, but it can definitely hurt an AEB. Search around, I'm sure you'll find opinions about it.
 

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2001 Passat wagon; 2016 Golf Sportwagen
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I get odd things all the time. Right now I keep getting the following:

1st code - MAF reading below lower limit.
2nd code - Oxygen sensor - 2nd bank - below limit, resistance too high.

All of this is a product of a bad MAF, the first code is right, but not because the engine is starved for air, but because I have a crapy MAF. The dealer is fighting me on it. - Mod the intake and they tell you that is the reason, never mind the KNOWN MAF issues with the 1.8t. I have swapped it our with a good one and no code...so you decide.

Anyway back to the point - so the other code is a result of the MAF reading incorrectly. The rest of the sensors process bad information and throw more codes. The car runs fine, but the codes keep showing up.

One bad reading at the top of the line will result in more as you move throught the system. I alwys try to fix the top of the system and usually the rest falls in line. ...
Same story here -- reman. MAFS from AZO was as far off calibration in the lean direction as my original unit was in the rich direction. A second new unit fixed everything.
 
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