CEL code P0234 on my FL5

[cxmk]

Hey guys, so I wanna start off by saying this is the first car I've ever modded, so I am new to all of this. About 2 months ago me and my buddy who has modded cars of his own installed a RV6 catted downpipe and a Milltek non-res exhaust. The whole installations went super smooth, he pretty much guided the whole thing and I assisted. I was aware I may throw a o2 sensor code at some point because of the downpipe. About a day or two later I did throw a CEL, and upon checking it I received code P0234 Turbo/Supercharger Overboost A condition. Had no clue what this was so I contacted my buddy and did some research. He wasn't really able to give me much info on it as well as the research I did I couldn't find any type r's with a similar issue. Did find a little info on the code and what it could mean but I cleared it and went on and it was all good until about a week or so ago, it came on again, and then started to come on with a lot of acceleration and boost pressure, I did pay attention to the boost gauge and nothing seemed to be higher than it was when my car was completely stock. Safe to say I'm super confused. My ECU is currently with Derek Robinson getting unlocked for the flash pro I got about a week ago.

Sorry for the super long message, I just wanted to give all the info I can, I appreciate any help I can get! Thank you.

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[madsedan]

Run it by Derek, have him check for codes and give you insight while he has the ECU.
Have you reached out to Rv6 to see if they have tips since that might contribute to the code?

 

[cxmk]

Run it by Derek, have him check for codes and give you insight while he has the ECU.
Have you reached out to Rv6 to see if they have tips since that might contribute to the code?

I actually just did this morning when I thought about it! I'm hoping he might be able to tell me something, and I have not reached out to RV6. That is a good idea thought I'm going to try and get in contact with them! Thanks man!

 

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[icman]

In what driving condition you got this p0234?

 

[cxmk]

In what driving condition you got this p0234?

Only when hard acceleration and building boost. Doesn't happen everytime but does throw the code when taking it to close to redline.

 

[madsedan]

You guys ever double check your rv6 dp install to make sure nothings loose? Air getting in/out of the exhaust because of lose

 

[CaryH]

Get rid of the downpipe.

 

[Two Step Performance]

It sounds like you are well on your way to a proper tune for your ECU. You can expect this to be taken care of for you at that point, assuming you are working with Derek on the tune or going with our TSP FL5 Stage 1 tune that he prepared for us.

I will note that if you do end up with an emissions related check engine light from the downpipe our TSP tune will not disable that.

TLDR: Stick with Derek and he will make sure you are taken care of. Hopefully there is nothing to it, but if so, he will help you diagnose it.

 

[Vito.FL5]

Factory exhaust is very restrictive. The turbocharger pre control is all based on modeled airflow through the turbine and out the wastegate, and since all values are modeled and not measured by sensors, if you make big changes on the system, pre controll can be way off, to a point that the PID control cant keep up, and it throws a code.

Ifthe DV hose popped off, you would be getting low boost instead of overboost.

By loading a tune that requests more boost, it will most likely go away, but if not, Hondata added some pre-control tables that you can use to fix it.

If you are tuning yourself and need assistance, let me know.

 

[PointByPatrol]

Sounds to me like something is loose. Check the oxygen sensors and exhaust flanges for leaks. Also check that you didn't knock the wastegate lever or arm.

 

[cxmk]

Factory exhaust is very restrictive. The turbocharger pre control is all based on modeled airflow through the turbine and out the wastegate, and since all values are modeled and not measured by sensors, if you make big changes on the system, pre controll can be way off, to a point that the PID control cant keep up, and it throws a code.

Ifthe DV hose popped off, you would be getting low boost instead of overboost.

By loading a tune that requests more boost, it will most likely go away, but if not, Hondata added some pre-control tables that you can use to fix it.

If you are tuning yourself and need assistance, let me know.

Gotcha, thank you so much for the info. Should be getting my ECU back today or tomorrow sometime so I will definitely probably have some questions for you, thanks again!

 

[scuderia_miso]

@cxmk did the tune resolve this issue for you?

I just experienced this code at the track today. Ran 3 sessions yesterday and was fine until the second session today.

I am running the TSP downpipe, PRL HVI, and AWE touring exhaust with stock tune.

I cleared the code and ripped it around on the street a bit and it hasn't returned.

 

[A.A.Ron]

I just experienced this code a day ago while doing a 2nd gear pull, CEL's on dashboard lit up right around redline. I have two mod's on the car, PRL HVI, and the MRT resonator delete. I too cleared the code and have done some test driving and it hasn't returned (yet).

 

[Slimbean_FL5]

@cxmk Did the tune resolve this issue? I have experienced the same overboost code after installing the RV6 catted downpipe and MBRP exhaust. I would peak at 25psi right before it throws the code. I did not want to tune my Type R just yet so had to swap back to my stock down pipe. Now boost is peaking at 23PSI in the mid range, which is nearly 4 psi higher then stock, and falling off close to redline. Ambient Air temps and humidity around the same when testing. No more code though. It honestly drove better with the stock downpipe and exhaust.

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