Check Engine Light

Question

Question

Check Engine Light

by Sienna222 Mar 30, 2017 11:26AM PDT

I have a 2007 Saturn Aura. The check engine light came on last week and a message on the dash popped up that said check fuel cap. I took it to the shop they tightened the fuel cap and it went off. A couple of days later it came back on with the same check fuel cap message I bought a new fuel cap and it went off again. Today it came on again. I don't know if it's still the fuel cap or something else. The mechanic suggested doing a smoke test. I don't want to pay for a test if it's just the fuel cap? Any suggestions?

Discussion is locked

2 Posts

- Collapse + Expand Details

Back to Auto Repair - Roadshow forum

r. proffitt · Answer 1 · Mar 30, 2017 11:37AM PDT

- Collapse -

Answer

To really get into this

by r. proffitt Forum moderator Mar 30, 2017 11:37AM PDT

You need the usual OBD reader and google (research) what the codes are telling you.

The cap has other reasons for that code/error to show like old vent lines that have failed. The smoke test is a good way to find that leaky line.

James Denison · Answer 2 · Mar 30, 2017 12:37PM PDT

- Collapse -

Answer

Part of that system on other cars...

by James Denison Mar 30, 2017 12:37PM PDT

..and probably on yours too is a vacuum test. When the gas tank is less than 3/4 full, the test will run to check for adequate vacuum in the gas tank to keep fumes flowing through the purging system into the combustion in engine. If it tries to establish a vacuum and the line has a leak in it, then the failure will trigger the "loose gas cap" error. The system begins at the vapor hose from gas tank and can track it back to find the other parts it goes through. The easiest test is for someone to have the gas cap on, and establish a vacuum on the vapor hose from the gas tank and see if the vacuum holds or not.

Check Engine Light

CNET Forums

Other Forums

Forum Info