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?
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. 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: Why is my car making a howling noise and blowing smoke when I accelerate? 2009 Mazda CX-7

Hello - there may be multiple problems contributing to the smoke and noise symptoms you are experiencing. The exhaust smoke you notice could be worn or damaged turbocharger seals, or worn piston rings, allowing oil to reach the hot exhaust....

Q: Engine light keeps turning on, 2006 Dodge Caravan

It sounds to me like the dealership simply tightened the gas cap and didn't charge you for it nor recorded the transaction. Not to worry though. I don't believe tightening the gas cap would be the proper repair. What you...

Q: Can you car still run if the ac compressor belt breaks

Hello. The car will not successfully run without a serpentine belt. The car may continue to run for a moment if the ac compressor belt breaks, but not for long. The belt also powers the alternator, which supplies engine with...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
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...