Q: P0171 & P0174

asked by on

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.

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.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. P0171 & P0174

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The car keeps displaying a power steering light on the dashboard followed by hardened steering

Toyota Corollas from 2009 and newer have electronic power steering and no power steering pump. The problem lies within the steering column and the electric power steering electronic control unit (ECU). The ECU has failed and is no longer giving...

Q: If I have done the oil change how can I reset it so the maintenance do soon b-1 doesn’t show anymore

Press the engine start/stop button to select the ON mode. Push the INFO button (right-side steering wheel controls) repeatedly untill the engine oil life indicator is displayed. Press and hold the SEL/RESET button for about 10 seconds. The Maintenance Reset...

Q: Red Lightning Bolt in dash

Hi There, The red lightning bolt indicates that there is a problem wit the electronic throttle control unit. This may be for a specific reason or may be due to a slight glitch. Try resetting the throttle control unit by...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...