Codes p0456 and p0431

2003 VOLKSWAGEN PASSAT

177,000 MILES • 2.8L • 6 CYL • 2WD • AUTOMATIC

IFYUSER

MEMBER
54 POSTS

I know a lot about car mechanics but i can't figure it out. I am getting a p0456 and p0431. I know you have to use a smoke machine but i don't have one. When i check the pids for the affected bank it reads .45 and sometimes it goes down to .15. Are both codes related. I already. Changes the o2 sensor in the affected side, a broken o2 sensor pigtail and messed with the vacuum lines in the secondary air injection system. Is the fuel pressure regulator hose related to the evap. Are both codes related. I want to see if it is the catalytic converter or not.

Oct 2, 2019 at 4:40 PM

KASEKENNY

✓ASE Certified Mechanic
18,907 POSTS

Hi,

These are completely separate systems and should be diagnosed separately. The P0456 is for the emission system and the o2 code is part of the exhaust.

The fuel pressure hose is not part of the EVAP system.

I included the testing for each code. Run through this and tell me what you find. I included the tests for a generic scan tool which is what I assume you have. Let me know if you have questions.

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Oct 4, 2019 at 1:22 PM