Po131

[Amaster]

I have a PO 131 code or system too lean code as I went and filled my Yukon today never gave any problems like this before except it was humid and rainy today the code was stored in the ecu as an old code but no light

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[wsteele]

What are the particulars of your truck? Year, model, flex fuel, etc.

 

[Amaster]

What are the particulars of your truck? Year, model, flex fuel, etc.

2011 Yukon xl slt 327 flex fuel just bought it 2 months ago

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[wsteele]

2011 Yukon xl slt 327 flex fuel just bought it 2 months ago

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What fuel did you have in the tank pre-fillup and what did you put in it?

 

[Amaster]

What fuel did you have in the tank pre-fillup and what did you put in it?

She had 3/8s of a tank of 87 proof and I topped it off with 89 proof cause it was somewhat cheaper

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[wsteele]

She had 3/8s of a tank of 87 proof and I topped it off with 89 proof cause it was somewhat cheaper

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Both like E10 gas?

 

[Amaster]

Both like E10 gas?

Yeah

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[wsteele]

Yeah

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OK so it isn't the Ethanol percentage being way off (like you had E10 and switched to E85 and the system didn't recalculate properly).

I probably would do a clean job on the MAF.

Does your scan tool allow you to look at fuel trims?

 

[wsteele]

Yeah

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Actually, I just looked P0131 up and my reference says you have a problem with your upstream Bank 1 (drivers side) O2 sensor.

Can you look at O2 voltages with your scan tool (i.e. live data)?

 

[Amaster]

Actually, I just looked P0131 up and my reference says you have a problem with your upstream Bank 1 (drivers side) O2 sensor.

Can you look at O2 voltages with your scan tool (i.e. live data)?

I think I can with my computer one I believe if it comes back on I'll look at it

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