Check Engine Light P0171 after oil change

[dp133]

Two issue with my 2013 Sonic. 1. Check engine light soon after recent oil change. Did it in Pepboys exton. I went back to Pepboys twice and they cleared the code, but never really fixed or had courtesy to inspect what is the reason for code. I still have the Check engine light on P0171 system lean bank 1. Any idea what could be the reason?

Secondly i hear the clunking noise from front suspension. Doubt it is the sway bar link. Driver side sway bar link is rusted and looks like a metal aftermarket one. Passenger side looks good with the factory genuine part made of plastic .
My car is 64K and i bought it around 63K from Del Toyota. Is there a recall available for swaybar link replacement?

RECALL # 12172 " Rattle or clunk"

 

[prindle16]

Lean condition could mean many things, but most commonly it's a vacuum leak. Could also be a problem with fuel delivery or o2 sensor but that's less common

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[Mark r]

Did you change the seal around the oil filter cap? Did you switch out the drain plug with the magnetic one?

 

[dp133]

Thanks for the response. Oil Filter was changed. i will have to check with pepboys about the seal and drain plug.

 

[Mark r]

So when I did mine I didn’t change the seal because it looked fine. It threw that code. I put 30 miles on the new oil and it went off. Hasn’t came on since

 

[dp133]

Suspect it was my oil filler cap. I removed it and then installed again with dexos text on cap reading your way. Check engine is now gone after driving for a while with resealed oil cap.

 

[prindle16]

Suspect it was my oil filler cap. I removed it and then installed again with dexos text on cap reading your way. Check engine is now gone after driving for a while with resealed oil cap.

That must've been it, putting that on loosely creates a vacuum leak

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[Vicarious]

I also have the lean code at the moment! I know in my case it wasn't a vacuum leak (Tried the propane test basically everywhere, and there's no audible leak). I'm down to:

• MAF sensor problems.
• Intake manifold leak.
• Injectors dying with age.
• Fuel regulator dying with age.

When I find my solution, I'll let you know, and see if there's any overlap.

 

[prindle16]

I also have the lean code at the moment! I know in my case it wasn't a vacuum leak (Tried the propane test basically everywhere, and there's no audible leak). I'm down to:

• MAF sensor problems.
  
• Intake manifold leak.
  
• Injectors dying with age.
  
• Fuel regulator dying with age.
  

When I find my solution, I'll let you know, and see if there's any overlap.

If you have an OBD2 scanner, you can check fuel trim levels. For example if lean condition is worse in low revs but gets better with high revs then it's likely vacuum leak. If it gets worse with high revs/load then there's a higher chance of it being fuel delivery (fuel pump/clogged injectors)

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[Vicarious]

If you have an OBD2 scanner, you can check fuel trim levels. For example if lean condition is worse in low revs but gets better with high revs then it's likely vacuum leak. If it gets worse with high revs/load then there's a higher chance of it being fuel delivery (fuel pump/clogged injectors)

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Yeah, already checked fuel trim, it's +30% across the board. If I were a gambling man, I'd assume it's likely injectors or regulator, because every now and again it stutters or surges, but outside of then, doesn't seem to run overly lean. Hell, can even give it a good boot and it'll happily rev up (Or as happily as our weak little engines can).

 

[prindle16]

Yeah, already checked fuel trim, it's +30% across the board. If I were a gambling man, I'd assume it's likely injectors or regulator, because every now and again it stutters or surges, but outside of then, doesn't seem to run overly lean. Hell, can even give it a good boot and it'll happily rev up (Or as happily as our weak little engines can).

Hmm if it's 30% across the board, perhaps it means 30% is the max trim allowed? Does it lower trim if you supplied propane at the air intake ?
Btw I'd recommend checking out Schrodingers Box YouTube channel for this type of diagnostic stuff, learned a lot there

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