Skip the auto shop - Our mechanics make house calls

Q: My car has a P0171 fuel system too lean code. The map sensor is ok at .95v, the fuel trim is at 122 and the 02 sensor is reading rich.

asked by on

My car has a P0171 fuel system too lean code. The map sensor is ok at .95v, the fuel trim is at 122 and the 02 sensor is reading rich.

My car has 19000 miles.
My car has an automatic transmission.

Hi there, thanks for writing in. The P0171 lean fuel system code can mean a variety of potential issues are at play, such as intake air leaks, a faulty front heated oxygen sensor, ignition misfiring, faulty fuel injectors, exhaust gas leaks, incorrect fuel pressure, lack of fuel, a faulty mass airflow sensor, or an incorrect positive crankcase ventilation (PCV) hose connection .

This depends on which O2 sensor is reading rich. There are often times two O2 sensors, one in front of the catalytic converter (pre-catalyst), which reads the oxygen levels prior to the conversion process and one after the catalytic converter (post catalyst) which reads the oxygen levels after the conversion process. If the O2 sensor after the catalytic converter is reading rich, this would suggest that the catalytic converter is not doing its job and may be clogged. I would recommend having an expert from Your Mechanic come to your home to diagnose and repair.

If you would like help with inspecting this code, consider having an expert automotive technician from YourMechanic come to your home or office to look at your car for you and diagnose the issue, and make any repairs, such as replacing your catalytic converter, if needed.

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
  • My car has a P0171 fuel system too lean code. The map sensor is ok at .95v, the fuel trim is at 122 and the 02 sensor is reading rich.

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: Poor acceleration and car jerking when going going on a mild/steep slope or carrying more people

Hi there, thanks for writing in. It sounds like you might be experiencing a problem with your clutch as opposed to the engine. Typically, around 130,000 miles, the clutch of a manual transmission will begin to develop problems engaging fully....

Q: Headlights won't turn off

Hi there. You are most likely going to run into problems installing this system if it requires manipulation of the daytime running lights; especially on a new Honda Accord. Typically this system can be linked to the security system (if...

Q: I have an Acura RXD 2014 and the horn suddenly comes on when I am driving especially when i am on a bumpy road.

Hi there. Based on what you've described it sounds like a possible broken spiral cable (clock spring cable) in the steering column. This wire is responsible for maintaining the electrical connections to everything on the steering wheel, including the air...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
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...