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Code system lean bank 1. P0171. 04 Scion xB 1.5. Change 02…

Code system lean bank...

Code system lean bank 1

Mechanic's Assistant: Just to clarify, what's the exact code? And have you tried to reset it?

P0171

Mechanic's Assistant: What is the make/model/year of your car?

04 Scion xB 1.5

Mechanic's Assistant: Are you fixing your xB yourself? What have you tried so far?

Change 02 change mas flow sensor plugs clean throttle body smoke intake no leaks

Mechanic's Assistant: Anything else you want the mechanic to know before I connect you?

On the scanner it shows calc load at 16% what does this mean Longfellow stays at 44.5% at idle and the light comes on code lean

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Answered in 4 hours by:
3/18/2018
Peter Bagley
Peter Bagley, Auto Service Technician
Category: Toyota
Satisfied Customers: 1,291
Experience: master tech at Toyota dealer
Verified

Hello and welcome to just answer, my name is ***** ***** master tech of over 40 years experience here to help. I cannot see or hear your vehicle so I rely on your patience and input to my questions so I can help you better.I have read your notes and have a question before we proceed.

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what does the voltage of the o2 censors read on the scanner and does your scanner show wave patterns?

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Customer reply replied 3 months ago
Yeah it does

ok with the wave pattern you can see if the o2 sensors are working properly as well as the cat functioning normal. also check the o2 sensors for voltage and let me know what you find.

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I will check back tomorrow to check your notes and help you further.

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Customer reply replied 3 months ago
Ok 02SB1-S1(V)=0.055
02SB1-S2(V)=0.8
02RLB1S1 ms131
02LRB1S1ms 66 these are the reading two different scanners

Yes that reads lean mixture still , seeing you have done most of the checks I would have you check the fuel pressure at the rails this is another factor.

P0171 SCION - Air/Fuel Mixture System Lean Bank 1

Possible causes; Intake air leaks EFI relay Faulty front heated oxygen sensor Ignition misfiring Faulty fuel injectors Exhaust gas leaks Incorrect fuel pressure Lack of fuel Faulty Mass Air Flow (MAF) sensor Incorrect Positive Crankcase Ventilation (PCV) hose connection ECM

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Customer reply replied 3 months ago
I have installed a new fuel pump new filter I smoke the intake no signs of leaks my last concerns are the fuel injectors the car have plenty of power idle rev up under load driving no signs of surgeon no engine shaking misfiring the engine runs smooth just at idle long-term fuel trim count up to 44.5% according to that number I know that it's going to set a code of lean Bank One when driving the car scanning the scanner long-term fuel trim countdown to low as 32% as it sits and idle it counts up to 44.5% I swapped out the Upstream O2 sensor and I swapped out the mass airflow they are you not know before the swap long-term fuel trim what count up to 47%

I know you stated a new fuel pump but could still have low pressure if relief valve is not holding properly so it would be a good thing just to eliminate that idea by checking the pressuer. the only other thing left I see is also a possibility of the exhaust manifold leaking sucking air in front of that sensor.

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Customer reply replied 3 months ago
Well.i guess i can smoke the exhaust from tail pipe and see what happens what is the fuel pressure spec. For the sicon xb 1.5L

over 30 psi . You can have someone stuff a wad of rags in the tail pipe tightly as you listen for air rushing out around the manifold when idling as well.

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Customer reply replied 3 months ago
Hello if everything else that I did check out and I still have a lean condition what else can be the problem at this point my back is against the wall the truck has 245,000 miles compression is 190 across the board I was hoping that you would be able to leave me in a Direction could the computer need reflashing or could it be both O2 sensor and a map sensor they are pretty pricey so I want to cover all basic before I spent over $200 on them item

Did you check the fuel pressure at the rails? What was it? before I proceed

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did you check all those possibilities in the probable areas I sent? There is no bulletin or common faults on this issue with your vehicle so we have to eliminate each one of those possibilities Try all the cheaper things first like doing that fuel pressure test at the rails, pcv - replace it. check for an exhaust manifold leak, after we eliminate those areas then we can consider the others. I know it's frustrating but we have to take a logical approach .

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My goal is to give you the best experience possible! I hope I have earned a 5 star rating! Please remember to rate my service by selecting the 5 stars at the top of the screen before you leave today. If you need more assistance, please use the reply box and let me know. In the process of helping you I will use sources from all different places that I feel fit and to the point that will speed up my help for you. This may include links, videos, shop notes and procedures as well as my own personal experience of over 40 yrs in the trade.

Peter Bagley
Peter Bagley, Auto Service Technician
Category: Toyota
Satisfied Customers: 1,291
Experience: master tech at Toyota dealer
Verified
Peter Bagley and 87 other Toyota Specialists are ready to help you
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Customer reply replied 3 months ago
Ok ill do them tests and ill get back to you on what i found or see
Customer reply replied 3 months ago
Ok i replace PVC valve fuel psi. Was 50 smoke exhaust no leaks found even with rags in the pipe how can i send you a picture of the scanner reading or a video so you can see what im seeing

YOU CAN DO IT AS AN ATTACHMENT ON THIS SIGHT

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Customer reply replied 3 months ago
Lol ok but how? Need Direction on how to do it
Customer reply replied 3 months ago
Oh maybe where it say add files next to send lol��

yes or if you make a u tube video send via link which would be the paper clip

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Customer reply replied 3 months ago
Well I'm going to do it off my cell phone the video after I do that how would I send it on this site
Customer reply replied 3 months ago
I have the video file on my phone how do I send it to you or on this website or if you can send me your cell phone and I sending it to you so you can see it

on this sight as an attatchment

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Customer reply replied 3 months ago
I have been trying and I have no success getting really frustrated trying if that's it says add files and nothing happens

are you putting it into PDF format?

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Customer reply replied 3 months ago
This is a heads up I figured out the problem it was clogged injectors I install used injector that took care of the problem long-term fuel trim went down to 6.3 at idle cruising speed it goes to 4.2 and lower I guess I could have did a injector leak down test and found the problem also

Yup that was one of the areas I mentioned prior that would cause that, I would have done an injector power flush and follow through with an injector cleaner in the fuel tank, It might be wise to use a fuel cleaner once every 3 or 4th fill up for maintenance.

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Customer reply replied 3 months ago
Yeah I'll let the customer know I had to injector on the back of my mind but the car was running so good plenty of power it did have a slight hesitation at take off call at the customer know I had the injector on the back of my mind but the car was running so good plenty of power it did have a slight hesitation at take all real slice real slight

got to watch those little guy's . if they clog up it starves for fuel but on the same tocken if they gum up at the nozzle and effect the spray pattern it works the opposite and has a richer mixture because it dosen't animize the fuel properly.

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Customer reply replied 3 months ago
Yep so true. Thamks my back was against the wall for a minute damn I took a break from it rethought it through total of item was the Master Flow Upstream downstream O2 sensor and the fuel injectors
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