Interesting problem with p0171 code n54

JiveSoulBro · 11-14-2016, 12:28 AM

Before I start, I do want to say that I have done endless research for the past week just trying to figure it out but no solutions have been found. Well here goes...

Currently I a CEL of p0171 and only that code. I understand that code can be triggered by weak fuel system, vacuum leaks, o2 sensor, etc. However after performing a boost leak test directly from the throttle body, the only leak that was found was the pcv. That being said if it was the pcv causing the problem, shouldn't it also caused a p0174 and misfire codes?

Additionally, I don't think that the fuel system is to blame because it would throw more codes at me and I would feel misfires, which i don't. The current symptoms are a small hesitation in throttle response, a little loss in power, idle 150rpm higher than normal.

My theory is that it the Bank 1 sensor 1 o2 sensor has finally quit on me causing the short-comings in performance. Since it has been noted that the o2 sensors go out at about 100k. The car currently has 128k.
Let me know what you guys think?

ArcticRik · 11-14-2016, 07:28 AM

Quote:

Originally Posted by JiveSoulBro

Before I start, I do want to say that I have done endless research for the past week just trying to figure it out but no solutions have been found. Well here goes...

Currently I a CEL of p0171 and only that code. I understand that code can be triggered by weak fuel system, vacuum leaks, o2 sensor, etc. However after performing a boost leak test directly from the throttle body, the only leak that was found was the pcv. That being said if it was the pcv causing the problem, shouldn't it also caused a p0174 and misfire codes?

Additionally, I don't think that the fuel system is to blame because it would throw more codes at me and I would feel misfires, which i don't. The current symptoms are a small hesitation in throttle response, a little loss in power, idle 150rpm higher than normal.

My theory is that it the Bank 1 sensor 1 o2 sensor has finally quit on me causing the short-comings in performance. Since it has been noted that the o2 sensors go out at about 100k. The car currently has 128k.
Let me know what you guys think?

I had this very code about a month ago, I reset the light and it hasn't come back again yet. I do notice a loss in power as well on acceleration. I will follow your thread to see what the outcome is!

JiveSoulBro · 11-14-2016, 11:14 AM

Quote:

Originally Posted by ArcticRik

I had this very code about a month ago, I reset the light and it hasn't come back again yet. I do notice a loss in power as well on acceleration. I will follow your thread to see what the outcome is!

I did reset the CEL multiple times and after around 10-20min of driving it keeps coming back.

Update to this morning. I started it up and it had a 1 bad stumble, I gave it a bit of throttle and she was fine and even started to idle like normal; even after being warmed up.

JiveSoulBro · 11-14-2016, 11:21 AM

I have decided to bite the bullet and ordered the Bosch 17098 Oxygen sensor for the Bank 1 Sensor 1 replacement. It was $89.24 shipped with 2-day shipping from Amazon with the Prime trial so I can also watch the Grand Tour for a couple weeks

I'll keep you guys posted on how it goes.

JiveSoulBro · 11-15-2016, 04:28 PM

UPDATE! Because the idle returned back to normal last night, I decided to clear the code again and see if it came back. It hasn't come back just yet. I do admit that on Saturday I poured a full bottle of Techron Complete fuel system cleaner and drove it about 70miles since then. It might be possible that the cleaner is helping. Keep in mind that this is still pre-O2 sensor replacement. The loss of power and throttle hesitation have decreased slightly but are still present. I will keep on updates.

JiveSoulBro · 12-01-2016, 06:29 PM

UPDATE! After changing the Front o2 sensor, it did not solve my issue with the p0171 code. I made a DIY on the change since I couldn't find one anywhere:
http://www.e90post.com/forums/showthread.php?t=1325770

PROBLEM SOLVED! On Thanksgiving I found that my Gas Cap was leaking fuel, which at the time I found odd because emissions checked it less than a month ago and it passed and I smelled no fuel.
Long story short I changed the Gas Cap and erased the code, and after 1 week of driving it has not come back. Yay!

bkwld · 12-01-2016, 06:58 PM

Glad it worked out!
Thanks for following up with updates!

Jarrod · 12-01-2016, 09:10 PM

Yeah good job. That code is a real bugger - I fought that one on a Jetta for months and never found it. Managed to get it to stay off long enough to achieve readiness and pass smog, then sold the car after disclosing it to the buyer. I think it needed a fuel pump and I didn't want to deal with it since I knew I was going to sell it.

11-14-2016, 12:28 AM	#1
JiveSoulBro New Member 12 Rep 14 Posts Drives: 2007 335i Join Date: Jul 2015 Location: Gilbert, AZ iTrader: (0)	Interesting problem with p0171 code n54 Before I start, I do want to say that I have done endless research for the past week just trying to figure it out but no solutions have been found. Well here goes... Currently I a CEL of p0171 and only that code. I understand that code can be triggered by weak fuel system, vacuum leaks, o2 sensor, etc. However after performing a boost leak test directly from the throttle body, the only leak that was found was the pcv. That being said if it was the pcv causing the problem, shouldn't it also caused a p0174 and misfire codes? Additionally, I don't think that the fuel system is to blame because it would throw more codes at me and I would feel misfires, which i don't. The current symptoms are a small hesitation in throttle response, a little loss in power, idle 150rpm higher than normal. My theory is that it the Bank 1 sensor 1 o2 sensor has finally quit on me causing the short-comings in performance. Since it has been noted that the o2 sensors go out at about 100k. The car currently has 128k. Let me know what you guys think?
	Appreciate 0 Tweet Quote

11-14-2016, 11:21 AM	#4
JiveSoulBro New Member 12 Rep 14 Posts Drives: 2007 335i Join Date: Jul 2015 Location: Gilbert, AZ iTrader: (0)	I have decided to bite the bullet and ordered the Bosch 17098 Oxygen sensor for the Bank 1 Sensor 1 replacement. It was $89.24 shipped with 2-day shipping from Amazon with the Prime trial so I can also watch the Grand Tour for a couple weeks I'll keep you guys posted on how it goes.
	Appreciate 1 ArcticRik166.50 Quote

11-15-2016, 04:28 PM	#5
JiveSoulBro New Member 12 Rep 14 Posts Drives: 2007 335i Join Date: Jul 2015 Location: Gilbert, AZ iTrader: (0)	UPDATE! Because the idle returned back to normal last night, I decided to clear the code again and see if it came back. It hasn't come back just yet. I do admit that on Saturday I poured a full bottle of Techron Complete fuel system cleaner and drove it about 70miles since then. It might be possible that the cleaner is helping. Keep in mind that this is still pre-O2 sensor replacement. The loss of power and throttle hesitation have decreased slightly but are still present. I will keep on updates.
	Appreciate 0 Quote

12-01-2016, 06:29 PM	#6
JiveSoulBro New Member 12 Rep 14 Posts Drives: 2007 335i Join Date: Jul 2015 Location: Gilbert, AZ iTrader: (0)	UPDATE! After changing the Front o2 sensor, it did not solve my issue with the p0171 code. I made a DIY on the change since I couldn't find one anywhere: http://www.e90post.com/forums/showthread.php?t=1325770 PROBLEM SOLVED! On Thanksgiving I found that my Gas Cap was leaking fuel, which at the time I found odd because emissions checked it less than a month ago and it passed and I smelled no fuel. Long story short I changed the Gas Cap and erased the code, and after 1 week of driving it has not come back. Yay!
	Appreciate 0 Quote

12-01-2016, 06:58 PM	#7
bkwld First Lieutenant 161 Rep 357 Posts Drives: E90 328i N51 Join Date: Apr 2015 Location: Renton, WA iTrader: (0)	Glad it worked out! Thanks for following up with updates!
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12-01-2016, 09:10 PM	#8
Jarrod Second Lieutenant 73 Rep 236 Posts Drives: 2012 E93 335is Join Date: Nov 2016 Location: SE USA iTrader: (0)	Yeah good job. That code is a real bugger - I fought that one on a Jetta for months and never found it. Managed to get it to stay off long enough to achieve readiness and pass smog, then sold the car after disclosing it to the buyer. I think it needed a fuel pump and I didn't want to deal with it since I knew I was going to sell it.
	Appreciate 0 Quote