Q: Why is my engine light on in my 2008 VW Jetta

asked by on January 04, 2017

I have a 2008 VW Jetta GLI. Its in pretty good condition. I just bout it in November, second owner. Its running smoothly. Anyway, about a month after I drove it, it started to not turn over right after fueling it. I would have to wait 5 to 10 minutes before the engine would start. This is around the time I noticed the engine light stayed on. This happened for 4 to 5 times in a row. I took it to Advance Auto to get a diagnostic test. It only showed a code for the gas cap. Even after tightening it, the engine light was still on. Eventually I decided to get them to test it again. This time the only code came up was fuel pump. I decided to see if it would help to put a fuel injector treatment in it. After a few days, the engine light went off, and I was able to start the car right after fueling without waiting. Now today, I am driving down the road and saw the engine light coming back on. And it won’t go off. I tried tighting the gas cap, etc. And its still on. Any ideas or experience?

My car has 121500 miles.
My car has an automatic transmission.

Hi there. If the check engine light came on for the gas cap and then for the fuel pump, either there is an electrical issue around the fuel tank causing the fuel pump to have a intermittent issue, or the evaporative purge solenoid is not working causing the light to come on. Check the fuel system out and look for any leaking fuel around the fuel tank. If there is no odor or any fuel leaks, then check the purge solenoid on the evaporative canister and see if there is power to it. If there is power to the solenoid and there is no power coming out of the solenoid, then I recommend replacing the purge solenoid . The purge solenoid is designed to trap and recirculate the vapors in the fuel system and if the valve is not working it would be not recirculating the vapors and could be venting the vapors. The vapor sensors would be picking up this and causing the engine light to come on. If you need further assistance with the fuel evaporative leak, then seek out a professional, such as one from Your Mechanic, to help you.

Hello. From what you are explaining this is due to a failure in the evap system. If you were having trouble with it after fueling then most of the time it is cause by a failure in the purge valve for the evap system. This valve should be closed when fueling, but if it is open then the fuel fumes will enter the engine causing it to have a harder time starting. I usually test the purge valve and the vent valve to see if they are fine, but it does sound like the purge valve. If you are looking to have this repaired, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the check engine light is coming on] https://www.yourmechanic.com/services/check-engine-light-is-on-inspection

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