Evaporative emissions system leak detection pump (Open/circuit) (Code P42000)

[Martin07]

Hey guys, I have babied my 2012 Audi A4 for two years now. Decided to throw CEL after coming back from store. Extremely frustrated do to the part that I first misdiagnosed the vapor canistor purge solenoid & had it replaced with no further diagnostic (My fault) Second left it at the mechanic shop to be further diagnosed since engine light was on right when I was about to leave. Left it for half a day & then a full day then they told me it could be the pump but they weren’t sure. the next day I called for an update which they said they still couldn’t figure it out so I decided to go for the car since I work 6 days a week & start at 4 in the morning which is hard to find a ride at that time. So when I arrived they told me they replaced the pump but said that was only part of the problem because CEL was still on & wanted to look more into it because they think it was the “wiring”. (Car runs just fine only problem is CEL) PLEASE HELP Audi Family. I really don’t want to waste anymore money or time. Hoping to be pointed in the right direction to anyone that has had this problem. I hope everyone is staying safe. Thanks in advance guys.


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[ROH ECHT]

Are you sure about that code?
Or is it P2400? Or some other?

Funny how the shop says it was only part of the problem. This means they replaced what they thought it to be and it wasn't the fault. They didn't explain why it was failed nor what else is wrong right? They only know it didn't fix the issue and they cannot return the part now. So you get to pay for their mistakes. Nice.



Hard to help just yet while not knowing the correct fault code...because I do not know if it is electrical or mechanical. Given the pump and N80 are replaced...it could be mechanical. Fuel cap may not be tightly sealed or there's a leak or split tube/hose somewhere. They would need to pressurize it to see if it is leaking. Last resort would be to determine if it is wiring or the ECU itself.

[Martin07]

Just realized it was P2400. I pressed a zero too many. No explanation is correct. The slight explanation was that it was a “bad” pump but code was still there because of a possible “wiring” issue. It’s a dad & son owned. I’ve trusted this shop with my older Audi but seems weird that they replaced a pump & didn’t fix the issue. The dad is convinced it’s a wiring issue but son tells me everything seems to look fine he said he even checked the fuel cap seal & surroundings. Son tells me it could be an ECU update but I don’t want to keep taking car to shop to be a money dump.


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[Martin07]

EDIT: Fault code (P2400)


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[ROH ECHT]

I believe the code P2402 usually points to replacing the pump.
I think your shop just replaced the pump and did zero testing...and passed along the savings to you when the lied saying it was part of the problem but not all of it. They cannot return it once they installed it and so they said what they said. Unfortunate.

You did replace the N80-EVAP purge valve/solenoid yes?

Given the N80 and LDP are replaced...it is likely to be a leak. And there are a bunch of places to be leaking from. Probably going to need it pressure tested or smoke tested. There is more to fixing this than replacing every replaceable part.

https://www.youtube.com/watch?v=y4heTf4rz7A

[Martin07]

Yeah not very happy with replacing the pump especially if it didn’t fix the CEL. Part wasn’t cheap either. Also frustrating due to the part that it’s only the CEL that’s the problem. Car runs just fine. Just didn’t want it to become a bigger issue. I thought it was an easy fix that’s why I took it to local mechanic right away. That’s why I left it after I made a mistake not to probably diagnostic it. Yes replaced EVAP purge valve/solenoid.


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[Martin07]

Yeah my point as well like why couldn’t they pressure test it or smoke test if everything else seemed to be fine.


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