why is there a recurring P0141/P0440 code?

Question

recently have had a recurring Check Engine and at first was just the P0440 code, which would stay on and then go off, and then after some time come back again. After some time my exhaust pipe needed to be replaced which brought up both codes. After being replaced the Codes stayed on but then went off after a few days of driving. That was about a month ago. While driving to work this morning the Codes came back on. My question is can a faulty Oxygen sensor cause both to come on? Or could this be more of an electrical problem than mechanical since they come on then go off?

Answer 1

For P0440 this is the FTP sensor, what happens is the FTP (Fuel tank pressure ) sensor does not give the correct pressure / vacuum . A faulty 02 sensor is not going to cause both the codes. there  circuit are no where near each other. What you can do for a P0141 is take out the 02 sensor P0141 is for the downstream 02 sensor, get a wire brush and clean out the side that the exhaust stream is impacting on the 02 sensor , then retest. if it works fine. if it does not, you need a 02 sensor