Q: Error code 171

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I want to know what's the issue for this code? Will O2 Sensor be the issue?

My car has 120000 miles.
My car has an automatic transmission.

Hello. If you are referring to trouble code P0171, then there may be a few different potential causes. P0171 is the trouble code for a lean condition at bank 1 of the vehicle’s engine. A lean condition occurs when the air fuel ratio becomes disturbed due to a lack of fuel, usually due to a fault in the fuel system. A lean condition can cause all sorts of issues such as a loss in power, fuel efficiency, and in serious cases even engine damage. Common causes are a faulty fuel pump, injectors, or fuel pressure regulator. Many other things, including a faulty oxygen sensor, can also cause the vehicle to cause that code to come up. The sensor would have to be tested to determine if it is what is causing the problem. If you are unsure, I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose the cause of the trouble code.

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