Check engine light PO171

[dustin3006]

So my truck got a check engine light PO171 bank 1 running too lean. It runs fine I've noticed no difference think its affecting my gas mileage however. I have the deck plate mod and k&n air filter. Today I cleaned my mass air flow and got rid of my k&n drop in filter for a regular one. My maf was extremely dirty. Not the main center sensor but the two wires inside of it. If this fixes the problem should I expect the light to go off or do I need to reset the ECU. My next step would possibly be check vacuum leaks or maybe clean throttle body? Any suggestions?

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[spartacus]

Check engine light

P0171 system to lean.I chased this code few years back and it was a pita. Mine ended up being the oxygen sensor that's above the cat or bank 1 sensor 1
You've cleaned the maf good but check the resistance between the contacts should be 2.2 - 2.7 kohms. Little higher or lower depending on the weather
Oem paper filter good
Check the pcv valve hose if it's got dried up oil or gunk clean it and replace the pcv valve if not replaced recently.
Check the O2 (sensor when cold) resistance should be 0.8 - 1.4 home
word of advice from experience. When you want to clean the throttle body remove it from the intake and get a new gasket or you might have idle and surge issue trust me I know. Good luck.

 

[19963.4lsr5]

Fuel filter could be getting clogged too.

If you have a scanner that reads live data you can look at the long term fuel trim for bank 1 and see what it is. That's where your code comes from. So you will be able to see if anything you did lowered the LTFT.

The MAF+IAT+ECT+TPS+rpm determine the fuel map chosen. The pre-cat O2 sensor sniffs the exhaust and makes any correction by adding or removing fuel which shows up in the two trim tables.


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[octanejunkie]

Probably O2 or AF sensors in the exhaust line. If it were your fuel filter you'd probably throw misfire codes under heavy load in addition to the lead code (due to detonation) but if you've never changed your fuel filter it wouldn't hurt.

Also fix the issue soon or your ECU will dump more fuel into the cylinders and eventually destroy your catalytic converter.

 

[dustin3006]

Probably O2 or AF sensors in the exhaust line. If it were your fuel filter you'd probably throw misfire codes under heavy load in addition to the lead code (due to detonation) but if you've never changed your fuel filter it wouldn't hurt.

Also fix the issue soon or your ECU will dump more fuel into the cylinders and eventually destroy your catalytic converter.

Which o2 sensor front or rear? And not familiar with af sensor. When and if I fix this problem will my check engine light go off by itself or will I have to reset it?

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[octanejunkie]

Which o2 sensor front or rear? And not familiar with af sensor. When and if I fix this problem will my check engine light go off by itself or will I have to reset it?

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CA emissions vehicles have 2 cats, an Air Fuel sensor and a wideband O2 sensor. Federal Emissions vehicles have one cat and two O2 sensors.

If the condition is corrected the CEL will often go away. If you want to clear it yourself just disconnect your neg battery lead for 10-15 mins. This will also reset the fuel tables in the ECU and your vehicle will recreate a fuel map. Not a bad thing unless you're on your way to pass an emissions test the same day.

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[dustin3006]

CA emissions vehicles have 2 cats, an Air Fuel sensor and a wideband O2 sensor. Federal Emissions vehicles have one cat and two O2 sensors.

If the condition is corrected the CEL will often go away. If you want to clear it yourself just disconnect your neg battery lead for 10-15 mins. This will also reset the fuel tables in the ECU and your vehicle will recreate a fuel map. Not a bad thing unless you're on your way to pass an emissions test the same day.

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No emission tests in Fl lol
I am worried about my truck relearning to run under the crappy conditions of being too lean
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[19963.4lsr5]

For all intense and purposes it is the sensor before the CAT. Your under hood sticker will tell you federal or Cali emissions. That will determine if it's a narrow or wide band sensor.


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