Skip the auto shop - Our mechanics make house calls

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?

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
  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: Shaking when in overdrive

Hi there. Check the fuel system and see if the fuel injector for cylinder number 2 is malfunctioning. The code P0402 means that the EGR is not functioning and the code P0174 means that Bank 2 is lean, which is...

Q: Gear shift locked up

Does the shifter move out of park? If the shifter moves but the car does not come out of park something has broken in your shifter. If you can not move the shifter out of park there is a problem...

Q: P0404, P0405, P0171, P0174

Hello. Thank you for writing in. Due to the p0405 code, you will want to start by replacing the sensor. This is typically easier and cheaper than replacing the EGR unit all together. If the light continues to illuminate, then...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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.