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Mercedes C180K OBD2 Code P0171: Frequent Check Engine Light with Normal Driving Performance

Model: Mercedes C180K Fault Code: P0171 Posted: 2014-05-22 13:51

The check engine light on my Mercedes C180K comes on repeatedly. After resetting the system, it returns within approximately 15 miles of driving. The vehicle performs well—excellent acceleration, smooth idling, and normal fuel consumption. Despite this, OBD2 code P0170 is detected. This discrepancy is confusing: why does a fault code appear when the car runs normally? What could be causing this issue?

Related fault codes

P0171

Comments (3)

Anonymous 2014-05-22 14:24

Refer to official OBD2 code explanation: http://www.obd-codes.com/p0171. Code P0171 indicates a lean air-fuel mixture in the engine, which may stem from issues like vacuum leaks, faulty oxygen sensors, or mass airflow sensor problems.

Anonymous 2015-06-05 09:32

I'm unable to start a new post. How can I clear the check engine light that appears on the dashboard? I believe this indicates an underlying issue that needs attention.

Anonymous 2015-06-06 08:30

The simplest solution is to address the root cause of the problem. Once repaired, the engine control unit will automatically turn off the warning light. It's recommended to have the vehicle scanned by a professional to identify the exact source of P0171.