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Check engine light code help

2K views 5 replies 5 participants last post by  pencilneck 
#1 ·
Just got the codes read on my 99 beetle for the check engine light. The code was: fuel system lean bank 1.
Does this have to do with why my gas mileage has been HORRIBLE??
thanks!!
 
#2 ·
What was the actual code number?
 
#5 ·
16555/P0171/000369 - Fuel Trim; Bank 1: System Too Lean

Possible Causes
Mass Air Flow Sensor (G70) defective
Intake System Leak(s)
Possible Solutions
Check Mass Air Flow Sensor (G70)
Check Fuel Pressure Regulation
Check Fuel Pump
Check Injectors
Check Intake System for Leaks
Check Exhaust System for Leaks
Check Secondary Air System for Leaks
Check Vacuum Pipes for Leaks
 
#6 ·
Please list your source:

16555/P0171/000369 - Ross-Tech Wiki

What would be good to see now is the fuel trim readings. This can offer some insight as to what all is going on. Measuring Value Block 031 shows fuel trim readings. If you don't have VCDS, then see if you can find some one in your area who does:

VWVortex.com - Vag-Com Locator searchable map style! Owners pm me your info requested in the thread

Here is a good articular about fuel trim values and what they mean to you:

Fuel Trim Info - Ross-Tech Wiki

My gut feeling is the MAF could be crapped out, and your fuel trim readings would be 18% and 25%. But until you get those readings, this is a open handed guess.
 
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