Q: P0171 & P0174

asked by on October 12, 2016

Shortly after an oil change, I got the following codes - P0174 & P0171. I am assuming it is a fuel system pressure issue. Are there any simple checks or fixes I can perform before taking it to a mechanic - hoping to save some money.

My car has 98000 miles.
My car has an automatic transmission.

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These two trouble codes are both related to the oxygen sensors located after the catalytic converter detecting that your vehicle is running lean. There could be a fuel pressure problem, vacuum leak, a vacuum hose left unplugged, an intake air tube not fully seated/loose, or any number of other possible causes. You may be able to do a visual inspection to see if any hoses were left off, or maybe a sensor left unplugged. If this happened within a day or two of the oil change, I would take it back to them and explain the situation. If nothing else, I would expect them to at least offer to do a visual inspection to be sure it wasn’t something they missed. If you’re still in need of help, YourMechanic offers a repair and diagnosis service preformed by a certified mechanic that will commute to your location to look further into these trouble codes.

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