P0456 - Small leak detected - Not N80 valve - FIXED
Hi,
My 02 1.8T got a CEL. Scanned it and showed P0456. Replaced the gas cap with one from Autozone. Still CEL came on. Removed and checked the N80 (purge valve) and it was slightly leaking (i can suck from the vacuum side without applying 12 V). Replaced with a new one and also replaced the check valve next to it (which was also slightly leaking). Did the vag com test with block 071 and still got error saying slight leak.
Went under the car and removed the 2 hoses from canister. One goes to engine side (N80) and other goes to tank. Tried to blow through each with mouth and N80, it was fine, but tank one, cant say for sure. It needs to fill up the tank i guess. Took some time to make it under pressure. Then connected the hose to the engine back to the canister and put my finger on the canister where the other hose connects. Now re-ran the test and it passed. So it confirmed that the Leak detection pump, its hose, canister, the hose to N80 valve and the N80 valve is fine. The fine leak is some where in the fuel tank area.
Next i tried to blow air to the hose which connects to the tank. Once the maximum pressure is reached, i closed it with my finger and tried to listen for leaks. Cant find any. Since engine was not running and it was a quiet area, it should have been easy to hear. I removed the fuel door mechanism and used a mechanical stethoscope to check for air noise around the bleeder valve / gravity tank. No sound at all. After all this tests like 5 minutes, when i opened the hose again, it had air in it. I mean it was still pressurized.
Now i am completely clueless. Any idea? Only smoke test can reveal it? Also planning to get an OEM gas cap and try again. Autozone gas cap clearly looks different.
Thanks in advance..
Hi,
My 02 1.8T got a CEL. Scanned it and showed P0456. Replaced the gas cap with one from Autozone. Still CEL came on. Removed and checked the N80 (purge valve) and it was slightly leaking (i can suck from the vacuum side without applying 12 V). Replaced with a new one and also replaced the check valve next to it (which was also slightly leaking). Did the vag com test with block 071 and still got error saying slight leak.
Went under the car and removed the 2 hoses from canister. One goes to engine side (N80) and other goes to tank. Tried to blow through each with mouth and N80, it was fine, but tank one, cant say for sure. It needs to fill up the tank i guess. Took some time to make it under pressure. Then connected the hose to the engine back to the canister and put my finger on the canister where the other hose connects. Now re-ran the test and it passed. So it confirmed that the Leak detection pump, its hose, canister, the hose to N80 valve and the N80 valve is fine. The fine leak is some where in the fuel tank area.
Next i tried to blow air to the hose which connects to the tank. Once the maximum pressure is reached, i closed it with my finger and tried to listen for leaks. Cant find any. Since engine was not running and it was a quiet area, it should have been easy to hear. I removed the fuel door mechanism and used a mechanical stethoscope to check for air noise around the bleeder valve / gravity tank. No sound at all. After all this tests like 5 minutes, when i opened the hose again, it had air in it. I mean it was still pressurized.
Now i am completely clueless. Any idea? Only smoke test can reveal it? Also planning to get an OEM gas cap and try again. Autozone gas cap clearly looks different.
Thanks in advance..