Skip the auto shop - Our mechanics make house calls

Q: I got my car check out and the codes come up was P0171,P0431,and P0174. How much will all this will be so I can start driving my c

asked by on

I got these codes and I need to know how do I go by of getting prices for these codes P0171, P0431, P0174 and get my car to run again.

My car has 214431 miles.
My car has an automatic transmission.

Codes P0171 and P0174 indicate the engine control unit is detecting the engine is running too lean - too much air and not enough fuel. P0431 indicates the catalytic converter is not operating at peak efficiency - not cleaning up the exhaust emissions properly. Odds are they are all related. Possible causes can be as simple as the wrong gas. This vehicle is not set up to run fuels like E85 and the likes, or "Flex-Fuel" capable as some vehicles are. Be sure that the gas you are using is not one of these "E" flex fuels. Other possible causes can be a vacuum leak. If the air intake tube is cracked/broken, or if a vacuum hose is disconnected or broken, the engine can draw in too much air, which will effect the air/fuel mixture. Odds are if there is a vacuum leak, the engine may have a higher idle. Other components like the mass airflow sensor, coolant temperature sensor, or oxygen sensor can be at fault. The mass airflow sensor tells the engine control unit how much air is being drawn in by the engine and uses this information to adjust air/fuel mixture, ignition timing,etc. The ecu relies on the oxygen sensor to detect how much unburned air and fuel are in the exhaust system and relies on the coolant temperature sensor to detect the engine temperature. As with the mass airflow sensor, the engine control unit relies on these sensors for input to adjust air/fuel mixture and ignition timing. A fault in any of these components can set those fault codes. Have a certified technician properly diagnose the fault codes to determine the exact cause. Since any of several components can be the cause, it would get expensive to replace parts at random.

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
  • Home
  • Questions
  • I got my car check out and the codes come up was P0171,P0431,and P0174. How much will all this will be so I can start driving my c

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: I have been quoted $ 650 to replace the rack and pinion on my 1992 buick riviera . Is that reasonable?

Hi Joseph. If the quote you received includes replacing the steering rack and gear box, as well as plumbing all power steering lines, and completing a suspension alignment, the estimate you have received is fairly decent. If you'd like to...

Q: Replacing a Cat 1

There are two catalytic converters on the Expedition, one for each "bank" of the engine. Converter 1, corresponding to Bank No. 1 of the engine (passenger side of vehicle) has quite a bit of pipe integral with the converter and...

Q: Car won't drive in gear.

Hello, I assume your car has a manual transmission. If you can push the clutch in and put it into a different gear, then the engine should rev and the car will move when the clutch is released and you...

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.