P0171 Diagnostic Trouble Code Discussion for February 2026
Fuel System Lean (Bank 1)
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| Help Request | Posted | |
| 2008 Saturn Aura XE 2.4L MIL Lamp on VIN: 1G8ZS57BX8 P0171: Lean Bank 1. This P0171 should be a simple fix but I cannot figure it out. The LTFT is 30% and STFT varies 5-10% at all RPM's, so that pretty much rules out a vacuum leak. But I did smoke test the induction system and found no vacuum leaks. Clamped off the PCV hose, br... |
February 03, 2026 | |
| 2020 Subaru Outback Premium 2.5L MIL Lamp on, Lean VIN: 4S4BTACC1L P0171: System Too Lean bank 1. Clear codes, start car, after roughly 60 seconds, fuel system goes in closed loop, short term fuel trim steadily creeps up to +34%, then long term fuel trim increases gradually to +35% and and short term will come down to +13.3%. S.E.S. will turn on and co... |
February 20, 2026 | |
| 2020 Subaru Outback Premium 2.5L MIL Lamp on, Lean VIN: 4S4BTACC1L P0171: System Too Lean bank 1. Clear codes, start car, after roughly 60 seconds, fuel system goes in closed loop, short term fuel trim steadily creeps up to +34%, then long term fuel trim increases gradually to +35% and and short term will come down to +13.3%. S.E.S. will turn on and co... |
February 23, 2026 |
