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Peter Zavarelli
Peter Zavarelli, Auto Mechanic
Category: Car
Satisfied Customers: 33304
Experience:  Technical Consultant at Just Answer
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Pete, Engine warning light. P0170 Fuel trim bank 1 warning

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Hi Pete,Engine warning light. P0170 Fuel trim bank 1 warning code on the OB. Computer says depollution fault message on the LCD. Local garage said the engine is sucking the oil cap back down like a vacuum when it's running. Any ideas? Might be a seal or one way valve?Regards,Andy.
Customer: replied 5 months ago.
I ran a live data and the most noticeable thing was a near constant negative number on the stft of between 3 and 12%
Customer: replied 5 months ago.
The O2 sensors were running within their normal voltages as well

Hi, my name is ***** ***** I will be happy to assist with this today.In some cases, I may need more info to assist better.I apologize for any delay.
I am here Sundays through Thursdays from around 5 am to 2 pm Mountain time.If you respond and I do not respond back right away I will do so as soon as I can.

I would have the engine ventilation system/PCV system checked/tested for any issues with restrictions or collapsed hoses.If the engine ventilation system is restricted this will cause a vacuum in the engine like you see here.This can cause codes to set as well.Unfortunately, I am not able to see how your engine is set up with this system to say for sure where to check but the ventilation system does need to be checked for any restrictions or issues.If this was already checked let me know.

If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service, your 5-star rating is appreciated ( should be a link to click on here or above).You can rate at any time and we can continue to work on your question as this will not close out your question.I work on delivering the best answer and help here but in some cases, it can be difficult to do without seeing the vehicle.

Thanks Pete

Customer: replied 5 months ago.
Hi Pete,Thanks for the advice. So could it be something as simple as a blocked air filter? Or would that not cause sufficient trouble to create the vacuum effect? Just worried about taking it to a Peugeot garage and them charging me a fortune for work it didn't need.Many thanks,Andy

That would also cause the vacuum issue here.If the engine air filter or air filter tubing is restricted or at fault this can cause this issue here as well.

You can check it yourself to see if the air filter needs replaced or if there is an issue with the air inlet tubing.

Let me know if you need anything else and feel free to rate my help here or above ( should be a link to click on ) as this is how I receive credit for my time, this can be done at any time and you can still come back here and reply if needed.Your 5-star rating is appreciated

Thanks Pete

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