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2001 Toyota Corolla P0171 - System Too Lean: Diagnosis and Fixes

Model: 2001 T Corolla Fault Code: P0171 Posted: 2007-12-17 21:45

Hello everyone, I own a 2001 Toyota Corolla with 150,000 miles. The check engine light has come on, and after taking it to AutoZone for diagnostics, I received code P0171 — 'System Too Lean'. I already tried cleaning the MAF sensor thoroughly using CFC MAF cleaner and disconnected the battery negative terminal for 10 minutes. After restarting, the check engine light went off temporarily, but reappeared after just a few miles. Given that this is a common issue on 2001 Toyota Corollas, I'm looking for input on what else might be causing this. Are there any other diagnostic steps I should take before taking it to a repair shop? Any insights or troubleshooting tips would be greatly appreciated! Thanks in advance.

Related fault codes
P0171
Comments (3)
Anonymous 2007-12-18 17:20

Check for vacuum leaks. Also verify fuel pressure — low fuel pressure can cause the engine to run lean. Good luck and please update with your findings.

Anonymous 2008-06-04 15:42

rkord24: I have a 2001 Toyota Corolla as well and am experiencing the same P0171 error code. If anyone has successfully resolved this issue, any advice would be very helpful. Thanks, cool.

Anonymous 2008-06-05 11:04

P0171 indicates the engine is running too lean. Follow the suggestions from MM — check for vacuum leaks and fuel pressure — then report back with your results for further discussion.