Audi Fault Codes P0491 & P0492 - Update

This is the very popular P0491 & P0492 issue with Audi V6 engines. This is a follow up to our original video where we were removing exhaust manifolds to perform this service.
We purchased the tooling to clean these passages with pressurized water. This was our first time using the tool and it works very well. As mentioned, the repair manual suggest front end in "service position". We chose to remove the front for better access which also made it much easier for us to make this video.
Tools can be purchased at audi.snapon.com/Home.aspx

[@Nuclearorigami]

Thanks from Swiss .You are step ahead in your audi deep dive repair ❤

[@11Vitty11]

Thank you for video. Waiting and appreciate for the new one without removing all front things.

[@thomasstach7410]

My Porsche 996 is throwing these codes so I am glad I found your great how-to videos on this topic. It'll help me to troubleshoot and potentially remedy my issue. I was wondering whether instead of pressurized water using a hand-pump spray bottle with E85 may be more effective with attacking and dissolving the carbon buildup?

[@HugoRuelas]

Thank you so much for this videos great information wish I could take my car to you

[@Snipah007]

How much time does the tool save in the process. Example if it was a 10 hour job before, what is it in hours now? Thanks!

[@jonathanbrowning8310]

Thank you for the video I have the P0491 on my a7 Audi 2015 is it a overnight job or will I be able to receive my car back the same day was taking it in in the morning but I have to be at work around 5 trying to see do I need a rental car or a ride to work

[@user-bz5rn6oq1l]

Where are you guys located interested in doing this with my audi s5 have both codes and won’t let me pass emission test

[@prestigewolf111]

What is the average cost for this procedure

[@DALVARADO714]

Hello what is this job called to get quote on it? I have the same codes coming up on my 2013 Audi A8 4.0

[@fai-tj1su]

Hello thank you for this incredibly informative video. My 3.0T S4 is going through the same problem. It had both the 0491 and 0492 code at first. I went ahead and took out the intake manifold and replaced the PCV, the breather hose, main coolant pipe, upper and lower radiator hose, and the water pump for preventative measure. I'm not left with P0491 only. what would be the best bet for removing this code? Thank you so much in advance.

[@premierautomotivediagnosti9432]

The only way to correct those fault codes is to clean the passage ways in the cylinder head. Thank you for watching our videos.

[@JoeSpaziani]

great videos would this process work on a bentley w12

[@100Ronster]

Thanks for this video. I'm wondering about debris in cat, does the carbon just get flushed out with the water?

[@premierautomotivediagnosti9432]

Good question. I believe there are mixed opinions about this. When we hit the carbon with our pressurized water, it seems to completely liquefy especially since we are hitting it with hot water. The water that is draining out of the catalyst is very black in color. I believe the carbon dissolves enough to completely pass through. We continue to clean until we get very clear water out of the exhaust pipe and verify the passages with the bore scope. We have never removed a catalyst post repair to get a better view but we feel like if there are any pieces that do not pass through, it is very minimal. We have cleaned the secondary air passages both ways and this is certainly the most efficient for us and our clients. We hope this helps. Thank you for watching our videos.

[@krivitely78]

Thanks for your video. I had both the P0491 and P0492 on my Porsche Cayenne 3.0 V6 Hybrid with 147000 km. This tool match it ? Do you have the process for dry the cylinders after cleaning ? Thanks.

[@premierautomotivediagnosti9432]

Hello, during this process the spark plugs are removed. Once the cleaning is completed, we suck out any water that may be in the cylinders with a fluid extractor and blow out the cylinders with compressed air. We then spin the engine over with the spark plugs out to push out any additional water and allow to air dry. The secondary air ports simply air dry. This tool does match your vehicle a and will perform properly. Note: we do not spin the engine over until the front clip is reinstalled and the transmission cooler lines are connected. We also have removed the fuel pump fuse and depleted any fuel pressure prior to this service. Thank you for watching our videos.

[@spitfireskatr7]

Thank you for this. I have a 2013 S4 throwing the p0492 code, I am an auto mechanic by trade and I have heard if this issue on this engine but never came across it. Naturally, it happens on my own car. I think I will invest in these tools. 1000 bucks is hard to swallow but taking those manifolds off sucks and hopefully I'll get to use it on some customer cars. Looks like you had the combivalves still on when you had the boroscope in the hole, do you leave them on for the pressure washing too? Thanks again for your video, very informative.

[@premierautomotivediagnosti9432]

Hello, I do agree with buying the tool. I assure you this is money well spent. I will not do another one by removing the manifolds because it is that bad. There is no need to remove the combi valves. Leave the combi valves attached and run the wand all the way back. If you have the tool, other techs and shops will send you those jobs. Remember to drop the exhaust behind the cats so the dirty water can run out and have the spark plugs removed during cleaning. Thank you for watching our video.

[@spitfireskatr7]

Thanks for the reply, of course I went to order the tool and its on backorder with no ETA. My luck. lol@@premierautomotivediagnosti9432

[@mghobadi75]

Hi Thank you foe helping 🙏 to show what is the problem it 8s. Is it under warranty of Audi Canada to fix this Code 0942? Thank you again

[@premierautomotivediagnosti9432]

Thank you for the kind words and for watching our videos.

[@zummrox]

Would this tool with the water damage/further clog the catalytic converters if they are already fairly old?

[@premierautomotivediagnosti9432]

VW seems to think the converters will not be affected and I would agree. As soon as this pressurized water hits the carbon, it liquifies. While performing this task, we can see the black water draining out of the exhaust pipe. Not saying it is impossible but we have yet to have a converter failure immediately following this process. Thank you for watching our videos.

[@exorbin]

my engine check light came on with these 2 codes on an 3.2 Audi A6 s line 2011, would you know how much the total cost would be too replace it all. please and thank you.

[@premierautomotivediagnosti9432]

Hello, We would suggest that you check with your local shop to receive an estimate for repairs. This could vary from shop to shop. Thank you for watching our videos.

[@jonmata7302]

What is the cost of those pressure washer adapters

[@premierautomotivediagnosti9432]

This tool was approximately $1k but well worth it all. Thank you for watching our videos.

[@user-bz5rn6oq1l]

Where are you guys located interested in doing this with my audi s5 have both codes and won’t let me pass emission test