Dabest
Ford Focus P0171 Code Issue - Need Help!
Summary of the thread
A 2006 Ford Focus with a P0171 code indicates a lean condition. The owner has already checked for vacuum leaks and replaced several components, including the spark plugs, ignition coils, fuel filter, and MAF sensor. The fuel trim values suggest the engine isn't excessively lean, and the fuel pressure appears adequate. The recommended next steps are to inspect the oxygen sensor for proper operation and check for exhaust leaks before the sensor. The owner plans to replace the O2 sensors and will update on the outcome.
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5 comment(s)
Dabest (community.author)
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Check the live data for the fuel trim values, specifically the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT). If these values are significantly positive, it indicates the engine is running lean. This could be due to a faulty oxygen sensor or a fuel delivery issue. Inspect the oxygen sensor readings to ensure they are fluctuating properly. If the issue persists, consider checking the fuel pressure to ensure the fuel pump is delivering adequate pressure. Let me know how it goes or if you have further questions!
Short Term Fuel Trim - Bank 1 % -6ish to 1ish Long Term Fuel Trim - Bank 1 % 3ish to 10ish Fuel Rail Pressure relative to manifold vacuum kPa 278.1195
CarlyMechanic
community_quotation:
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Short Term Fuel Trim - Bank 1 % -6ish to 1ish Long Term Fuel Trim - Bank 1 % 3ish to 10ish Fuel Rail Pressure relative to manifold vacuum kPa 278.1195
The fuel trim values you provided suggest that the engine is not running excessively lean, which is good. However, the P0171 code still indicates a lean condition. Given the fuel rail pressure seems adequate, the next step is to inspect the oxygen sensor for proper operation. Ensure the upstream O2 sensor is fluctuating between 0.1V and 0.9V. If it's not, it might be faulty and need replacement. If the sensor seems fine, consider checking for exhaust leaks before the O2 sensor, as they can also cause lean codes. Let me know if you need further assistance!
Dabest (community.author)
community_quotation:
community_author_wrote_on
The fuel trim values you provided suggest that the engine is not running excessively lean, which is good. However, the P0171 code still indicates a lean condition. Given the fuel rail pressure seems adequate, the next step is to inspect the oxygen sensor for proper operation. Ensure the upstream O2 sensor is fluctuating between 0.1V and 0.9V. If it's not, it might be faulty and need replacement. If the sensor seems fine, consider checking for exhaust leaks before the O2 sensor, as they can also cause lean codes. Let me know if you need further assistance!
I went ahead and ordered O2 sensors this weekend. They should get here tomorrow or Thursday and I can update then. Thank you for now
CarlyMechanic
community_quotation:
community_author_wrote_on
I went ahead and ordered O2 sensors this weekend. They should get here tomorrow or Thursday and I can update then. Thank you for now
Sounds good! Once you replace the O2 sensors, monitor the fuel trims and check if the P0171 code clears. If the issue persists, we can explore other possibilities. Keep me updated, and feel free to ask if you have any more questions!
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FOCUS
CarlyMechanic
Check the live data for the fuel trim values, specifically the Short Term Fuel Trim (STFT) and Long Term Fuel Trim (LTFT). If these values are significantly positive, it indicates the engine is running lean. This could be due to a faulty oxygen sensor or a fuel delivery issue. Inspect the oxygen sensor readings to ensure they are fluctuating properly. If the issue persists, consider checking the fuel pressure to ensure the fuel pump is delivering adequate pressure. Let me know how it goes or if you have further questions!