Ok. my CEL when on tonight, I ignore it and drove 1/2 mile to gas station. Turn off the car and put some gas, when I start the car again the CEL disappeared.

I have 1/4 gas before I drove to the gas station.

Now can I still read the CEL even though the light went out already or do I have to wait again for it to lit up for me to read it?

Thanks

 

Yes, You can read the computer if the light was on. The code that came up will be stored into the computer untill you fix the problem and clear the light. The code will prob. be an evap code. Let me know if you still have problems ive invested thousands of dollars in diagnostic scan tools.

 

its possible it couldve just been because someone didnt screw your gas cap on tight enough.....its still worth a read though

 

Yes this is true hence the code for an evap system leak