Q: Engine Light On - System Too Lean.

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The engine light is onn. When the computer was checked the problem, the code was P0171 - System Too Lean (Bank 1). The light only came on after the most recent oil change. What is causing this problem. If that question can't be answered, is the problem with the powertrain system or transmission system or neither?

My car has 52000 miles.
My car has an automatic transmission.

Hi there. Check the mass air flow sensor (MAF) and see if it got unplugged. When the oil change was done, most likely the air filter was checked and the MAF sensor was disturbed. Also, check all of the vacuum lines and make sure that they are all in good shape and not cracked or broken. Replace any cracked or broken vacuum lines. If you need further assistance with your check engine light on, then seek out a professional, such as one from Your Mechanic, to help you.

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