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Ross, Diagnostic and repair technician
Category: Car
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Experience:  Licensed diagnostic and repair technician
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Vauxhall Zafira 1.8 petrol diagnostic code P0170. According

Resolved Question:

Vauxhall Zafira 1.8 petrol diagnostic code P0170.
According to reader this code indicates Fuel trim malfunction - bank 1.
Can you please enlighten me as to what this actually means and what the possible problem could be.
Submitted: 10 months ago.
Category: Car
Expert:  Ross replied 10 months ago.
Hi Ruth, my name is***** am a diagnostic technician and look forward to working with you.The code P0170 can have several causes. The code alone does not pinpoint a specific cause but is indicating that somewhere on the fuel system, there is a problem with controlling the fuel injection quantity.To give you a rough idea of exactly what it means, I will break the code down. Fuel trim malfunction (bank 1) Effectively means the engine is unable to adjust the fuel/air mixture to what it intended on bank 1. Your engine only has one bank of cylinders so bank 1 means any four of the cylinders. The engine control unit detects how well the fuel is burnt (too much or too little fuel) by use of an oxygen sensor on the exhaust, it responds to this by adjusting the fuel trim to either give is slightly more or slightly less fuel to keep it at optimum mixture.Firstly, the intake system needs to be checked for air leaks, even a small leak can cause this code.Next is to check the Mass air flow meter is reading correctly, this can cause havoc with the fuel trims if it is reading incorrectly.The 02 sensors can also cause this if they give an inaccurate reading or have failed.Finally would be fuel pressure, if the fuel filter is blocked, or the pump is failing it can cause pressure to drop too low to the fuel injectors. All of these are relatively simple to test and diagnose and can usually be sussed out within an hour of diagnostic time and is usually a simple case of replacing a sensor or split air pipe.
Expert:  Ross replied 10 months ago.
I hope I’ve provided the information you were seeking. If you need more help, please use the reply tab to continue our conversation. If you do not require further assistance, kindly rate my service. Thank you, Ross.
Ross, Diagnostic and repair technician
Category: Car
Satisfied Customers: 1159
Experience: Licensed diagnostic and repair technician
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Customer: replied 10 months ago.
Thanks for prompt reply,Ross,and has helped as there are a couple of issues we didn't think of.
Have shown this to my daughter(her car) and she asked me to mention the following to you. Hope
you don't mind.Her car went into garage,initially,with above problem but when they checked it they said it was reading "rich exhaust".
However,went to collect car after repair? but it wouldn't fire up so she had to leave it for them to check over,again!!!!
Over a week later,and numerous phone calls by her,it has taken a nasty email to have her car fixed.
Went to collect car last night and she was told they had cleaned out the throttle body but this would have to be
replaced soon.Car ready though,off we went. One mile along road had to turn right back to garage.The code was what came up on her dads wee diagnostic reader and she had a similar problem 2 yrs ago and knew
it had been the fuel filter then.
Does "rich exhaust" or "throttle body" mean anything to you.
Thanks again

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