i know ive wrote plenty of times and got a few responses but i still cant get to the bottom of it. has any one had this p0175 code? know i cant be the only one. for more info on this check out my other threads. any kind of help would be appreciated!
MAF may be dirty, Failed O2 sensor, leaking fuel injector, Fuel rail pressure sensor may be bad. There is a lot that can cause this code. Most of the time is a dirty MAF, clean it and clear the code. See if it comes back. If you have a scan tool look to see if the B2S1 O2 sensor is biased rich. Make sure that none of your intake or any vacuum lines are leaking.
no i have no vaccum leaks and i just replaced my upper and lower intake gaskets. both of my downstream o2s read low. the uppers stay high. thats why i replaced them. same thing still.fuel pressure good and holds pressure good. is there a way to test my cats? that was my first suspition. i had a new catback system put on in the fall and it was downhill from there. just keeps getting worse and worse. any input?
you can check the cats by watching the o2 sensor voltage, if the back switch at the same speed as the front the cats are shot. the rear O2's should not switch voltage very often, the fronts should switch a lot, if they match voltage the cats are toast. If your uppers o2's are reading high voltage 0.7-0.9v all the time then the motor is running rich. Maybe a broken fuel pressure regulator?
thanks or the info. the only thing i know is that when i had a livewire test done the dude said the downstreams were reading low. i seen numbers in the single digits. seems like the uppers were in the 60-80 range.(im not a complete retard but im not sure what the numbers meant). the guy said the uppers and lowers should read opposite of eachother. you know when the uppers drop the lowers should get higher. he said they were bad because they read soo low. i wish i knew some mechanic around here(muskegon,mi) that actually knew what he was talking about. i never bring my stuff in with the exeption of this problem. now the first mechanic visit ive had in years was an idiot! oh, my fuel pressure was good and held pressure so my regulators shouldnt be bad. right? anyways hope you write back soon. got a couple more questions for you. thanks!
If the fuel pressure is ok then dont worry bout the regulator. Couple things that will help, do you have access to a scan tool? and do you have two CATS or 1? the 60-80 you saw is actually voltage, at .600v-.800v the upper 02's are indicating the motor is running rich. One easy test is to unplug the rears and see if the voltage on the uppers levels out. (the should be switching between .1v-.9v. If they start switching again, replace the rear 02's. Also make sure there is no exausht leaks from the uppers to the lowers.
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