Q: Too lean in bank 1 and bank 2

asked by on

My truck has recently been serviced. I have had the O2 sensors replaced. Check engine light came on and said P0171 and P0174 too lean. Is that issue the amount of air that is getting into the system and not enough fuel?

My car has 270000 miles.
My car has an automatic transmission.

Hi and thanks for contacting YourMechanic. When the engine becomes too lean, then combustion chamber becomes very hot causing the head gasket to burn, valves begin to burn, and the rings being to seize up. Check the camshaft sensor and MAF (mass air flow) sensor to ensure that they are working correctly.

The reason the sensors are pulling up the codes is they are working and saying that the system has loss of fuel (hydrocarbons). Also, check the fuel injectors to ensure that they are operating properly. I recommend putting in an injection cleaner to clean out the injectors for a better atomization spray. If you need further assistance diagnosing your Check Engine Light, then seek out a professional, such as one from YourMechanic, to help you with your vehicle.

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. Too lean in bank 1 and bank 2

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 3 code on my car P0431, P0174, P0305

Noise in exhaust systems occurs due to leaks as well as internal failure of the baffles in the muffler or resonator. So, just because there are no leaks, doesn't mean the exhaust system will be noise free. An [engine/exhaust noise...

Q: My Small SUV is squealing while I'm slowing down and I'm not pressing on the brakes.

Hi there. The noise could be the brakes indicator rubbing on the rotors on the front of your vehicle. This is the reminder to have the brakes replaced. If the brakes are new or have lots of friction material remaining,...

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.

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...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...