Skip the auto shop - Our mechanics make house calls

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.

A: These two trouble codes are both related to...

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?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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: Car shakes and vibrates

A concern like this can be produced by a number of different things. Such as; a large vacuum leak in the intake system, lack of airflow to the intake system, lack of fuel delivery caused by a failing fuel pump,...

Q: Check engine light on

There are a wide variety of reasons why the Check Engine Light switch may be still on. In this era of Honda pilots, there was a known issue related to the transmission torque converter clutch solenoid which controls the engagement...

Q: Can an overheated engine cause my car to not drive ?

A blown head gasket may cause a number of different symptoms. A head gasket that fails between cylinders will generally cause a misfire and potentially compression leaks from one cylinder into another. Low compression will eventually result in a rough...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
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...