P0171 – System Too Lean (Bank 1)

System: Engine
Dashboard light: Check engine light (MIL)
Check-engine blink code: —
Applies to: Generic OBD-II meaning. Not every code is used by this car.
Description: System Too Lean (Bank 1)
Detection / symptoms: 1.Check engine light on 2.You will more than likely not notice any drivability problems, although there 3.May be symptoms such as 4.A lack of power 5.Detonation (spark knock) 6.Rough idle
Possible causes: 1.A code 2.P0171 3.Has happened 4.The MAF (Mass Air Flow) Sensor is dirty or faulty 5.Air filters may cause the MAF to become dirty if the filter is over-oiled 6.There is also an issue with some vehicles where the MAF sensors leak the silicone 7.Potting material used to protect the circuitry
What to check: 1.Read the code and freeze-frame data with an OBD-II scanner 2.Check the connector and wiring of the part named in the code 3.Test the part with scanner live data or a multimeter, using the values in the repair manual 4.Fix the cause, clear the code and test-drive
Confidence: medium (generic OBD-II definition, not checked against the factory manual for this car)

Generic OBD-II meaning (obd-codes.com), not checked against this car's factory manual. Clear the code and test-drive to confirm it returns. Search all fault codes · Common problems · Warning lights