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Bensk8s
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3 Posts
Discussion Starter #1
Hey guys so recently as of yesterday my CEL came on in my 2016 3 at 31,000. I checked the code and it was P0171 running too lean. I checked to see what the possible causes were and from what I've read there's a lot, MAF, MAP, PCV, fuel injectors, ect. So just to narrow down my search. What componets cause this issue that I should look at first? Thanks!
 

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Super Moderator
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5,250 Posts
Yes, dealer issue. If you go poking around under the hood throwing parts at it trying to fix this, the warranty is not going to cover it when you eventually give up and take the car to the dealer.
 

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aka Goodwrench
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28 Posts
Mazda declares a P0171 when:
•*The engine is idling or the vehicle is driven, the fuel feedback correction amount (30 %) is the threshold or more, and the fuel learning correction amount is the specified value (15 %) or more for 10 s or more.

• The engine is idling or the vehicle is driven, the fuel feedback correction amount reaches the upper limit (25 % or more) for 20 s or more.

This is adding fuel to correct a lean (too much air) condition. 30% is a fairly large air leak. Look at all the hoses and see if anything
looks out of place or cracked.

Sounds like you have an OBD scanner, if so post the freeze frame data for:
• short term and long term fuel trims
• Calculated engine load
• RPM
•*Mass air flow
•*O2 sensor lambda wide range

To test your MAF, at hot idle it should report around 1.8 - 2.0 grams/sec.

Or take it to the dealer and let them figure it out while you have a coffee :)
 

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Bensk8s
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3 Posts
Discussion Starter #5
I'm a actually mazda tech learning as I go haha. I checked my maf values everything seemed fine. I asked one of my co workers and he said the MAF probably read something that it didn't like. Like maybe the oil cap was loose or the dipstick was out a little. Cleared the code, no CEL since then. ?
 
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