tonyvu

hey guys, these 2 codes keep pulling up after erase, I searched the entire forms for the answer but coming up short. If there any DIY repairs that you guys can lead me to would be greatly appreciated !
P2024 evap emissions fuel vapor temp sensor circuit
P2026 evap emissions fuel vapor temp sensor circuit LOW voltage

tonyvu

bump just an update its a permeant code p2025, any help would be greatly appreciated

SMac770

Those codes involve the EVAP system at the fuel tank in the back left of the vehicle.
https://www.ilcats.ru/audi/?function...70&language=en
Item 3 is the J909 fuel tank leak detection control module with integrated G400 fuel pressure sensor. The fuel tank temp sensor is in the J909.

A TSB on a different J909 issue, but gives you visuals: https://static.nhtsa.gov/odi/tsbs/20...16677-9999.pdf

The scan tool workshop manual documents multiple triggers for P2025, so without the complete DTC info, hard to guess which condition exists. In the end, it's likely something has gone bad with the temp sensor circuit in your J909 and it'll have to be replaced.

https://static.nhtsa.gov/odi/tsbs/20...08199-0001.pdf
This TSB is for a different vehicle of the era. What I found curious is P2025 is a possible exhibit. So while that TSB is for a vehicle design issue, maybe the trigger is related to your broken scenario. Maybe something is letting the J909 get soaked?

In the end, someone is going to have to get up in there and see what's up with the J909.

tonyvu

if im correct it talks about the charcoal canister , actually before my p202* codes there where these 2 codes before i bought the car. p310B and p0456 which ended up going away after reseting the CEL, and then one day i ran the car to beyond empty and then i started up the car and the code p202* came up while the othere 2 disappeared.

thinking should i just replace the charcal canister or just the pressure switch. what do you think @SMac770

SMac770

P310B is not in the generic scan tool workshop manual for the CPM (you don't mention if you have the CAE or CPM engine). P0456 is EVAP pinhole leak.

P301B is not related to EVAP at all. http://wiki.ross-tech.com/wiki/index.php/P310B/012555 Probably because you ran the tank dry and the G410 detected an instance of insufficient fuel pressure coming from the in-tank pump. Could that scenario flag a pinhole leak? Don't know. Is it possible that running the tank dry allowed the temp sensor to be exposed to a non-fuel liquid like air moisture? Will it self correct with time? I don't know any of that.

The charcoal canister is just a canister. As long as a smoke test shows no leaks, there's nothing more that can really happen involving that, I imagine.

If you wanted to take a blind DIY parts cannon action, replacing the J909 (that item 3) is the thing to try. I don't know if there are any other computer side actions you can attempt with the J909. The workshop manual seems to imply there's little to nothing you can invoke/adjust using the diag tool. But I'm not an Audi tech that deals with EVAP issues day in and day out.

tonyvu

yea im goin gto give the J909 a shot and see how it goes looks easy enough lol i think...... just i cant find any write ups on it

thank you for all the hints adn tips this was awesome !