2014 Q5 P029900 code help!

[Brianl764]

So i just recently bought a used 2014 Audi Q5 2.0t with about 100k miles. At first everything was good but when i got on it a little bit it threw the P029900 code. After further thought I feel I do feel a slight rattle at low rpms on light load through the pedal and also acceleration is sluggish until boost fully kicks in resulting in some slight lurches on auto shifts. I will check the wastegate actuator in the morning but after self evaluation I am almost positive its the wastegate and I need to replace the turbo. I just threw a heavy penny on the timing chain and now to replace the turbo I would realistically want to wait till the end of the year aka another 6 months. I only drive to work two days per week and if I'm not getting on it significantly and drive relatively easy can I last out 6 months with a loose wastegate without any long term damage? Please help!

[Smac770]

It'll be the turbo wastegate, same as it always and frequently is with the IFI turbo on the EA888 Gen2 2.0T. There are many approaches out there to "hacking" the situation to retighten the wastegate. But part of that depends on what's actually wrong. If it's the wastegate bushing in the turbo housing itself, yanking the rod tighter is not likely to accomplish much. If it is just the actuator rod to wastegate arm connection that's loose, then the rod mods are an approach. But keep in mind that the rod to arm connection is likely loosening because it's literally wearing through the wastegate arm. From my original turbo:

IMG_0097d.jpg

And another guy had the issue where the rod c-clip came off so the rod wasn't even moving the arm.

There is the anti-rattle clip you can get to slap on there if it's not too bad; see how that cleans up the slop. 06J145220. Looks like 06J145220A is for the transverse applications and 06J145220B is for the longitudinal applications. https://www.fcpeuro.com/products/aud...udi-06j145220b

[silver_tt]

Mildly surprised the turbo is giving at only 100K miles. I have the same car with coming up on 135K miles and never had an underboost code. If you had the afterrun coolant pump recall done the turbo warranty was extended but we are likely near the end of that now -- for example I had it done right when I got the notice but my extended turbo warranty expired at the end of last year. Maybe Audi would give you some goodwill but that would be off the retail pricing so probably not worth it anyway. It is not a good idea to continue to drive the car for long periods with a failing turbo, it can cause other issues but I am sure many have done it a few months or longer. They aren't cheap but if it was my car I would buy a new IHI turbo for $1600.

[Brianl764]

I heard using the clip is only to use before the actuator arm gets sloppy and once it’s loose the clip is useless? I just don’t want to cause more problems to it, boost lag is the least of my worries I can deal with the NA hp for now as I don’t drive aggressively or often.

[Brianl764]

I mean if it’s an under boost code it’s just not closing fully and I don’t think under boost would cause any long term issues no? I get overboost would put more pressure on the turbo and motor causing some long term effects for sure but shouldn’t boost lag be the only effect?

[silver_tt]

If you take the turbo off the engine doesn't just turn into a naturally aspirated engine. It was designed for use with a turbo so when you have underboost the engine has to work harder and will cause the ECU to adjust your fuel trims which can cause other problems like in the cylinders and exhaust system. Either way it is not a great idea to continue to drive the car longterm with a failing turbo. If you're pressed for cash maybe you could pickup a used one off of a low mileage wreck or something of that nature.

[Smac770]

There was an extended warranty (7yr/70k) on the turbo originally, it was such a problem with wastegate looseness. But I already had 90k on it by time my P0299 started being consistent. That you have problems at 100k is no surprise to me. The clip did actually make it work well for a few days, then it was back to normal.

I've had P0299 for a very long time, just means you have practically no power under 2.5k unless you floor it. If you live in an emissions area, the MIL light will fail you right off the bat though. Only time of the year I have to care about it, clear DTCs, don't break 3k rpm for 10-20 miles to set readiness, get tested, don't care for another year. Don't waste your time with ebay "rebuilds". Was worthless for me. Either get a new one ($1k) or just ride it out.

[silver_tt]

By 2014 I would have thought those early MY turbo issues were resolved. Aside from emissions it will cause the ECU to make the engine run rich, which can cause other issues in the long term. For a resolution I also would just get a new one. Is has been revised several times:

https://www.audiusaparts.com/oem-par...fold-6h145703s

If you want to buy OEM (~$1100) or OE (~$1600) will depend on if you think there is a difference. From what I have seen in the last 20 years and know of the automotive industry, they are not the same thing. In the end it may come down to how much you value your time or what you are paying to have the work done, and possibly re-done again later, and the reliability of the replacement part.

[Brianl764]

Appreciate the help guys. Yeah I think I’ll just gently drive it until I can replace it asap and just go full rebuilt turbo.

[grayjay]

You can DIY replace the worn turbo wastegate, shaft, housing bushing and arm with parts available on ebay. Requires tack welding the new arm & shaft together after fitting to the turbo. Mine was rattling and throwing codes before I did this, has worked fine since the wastegate repair. Much cheaper than a full turbo replacement if there is nothing else wrong with the CRHA. Youtube has tutorials for how to perform the flapper replacement.

https://www.ebay.com/itm/22515303679...Bk9SR8DbrvCnZA