Q: I failed a smog check with the codes PO171 & PO174, saying the system is too lean on the bank 1 & 2. Can you tell me what the problem is?

asked by on January 03, 2017

under the OBD systems check, I failed with the codes PO171 & PO174 , saying that the system too lean on bank #1 & bank #2. so I failed the smog test. Can you help me out here & tell me if this is a easy fix that I can do, or if its a major ordeal to get it to pass a smog test ?

My car has 240000 miles.
My car has an automatic transmission.

Hi there. When the two codes P0171 and P0174 come up for a lean system on both banks of your engine, then either all of the fuel injectors are not working properly or your fuel pressure has dropped. Check the fuel pressure on the fuel rail and see what the pressure is at idle and when loaded. If the fuel pressure is less than 45 psi but greater than 15 psi, then the pressure regulator needs replaced. If the pressure is lower than 15 psi, but has more than 1 psi, then the fuel pump needs replaced. If you need further assistance with your emissions problem, then seek out a professional, such as one from Your Mechanic, to help you.

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