Check Engine Light comes on ... No Error Codes

[Old Coot]

So, for about a week now my check engine light has come on intermittantly and I finally got the Trailblazer down to the garage to get it checked out. The tech connects up the latest Snap-On code reader and tells me the only error codes that show are historical data from a brake sensor and a turn signal circuit open. There were no engine codes!

What's going on?

 

[CaptainXL]

Usually when this happens it because of the gas cap. Do you have any rust on the edge of the filler neck?

Also, not knocking your local garage...but you should head on down to AutoZone or Advance Auto to get a second opinion. It's possible that the garage didn't have the correct settings when trying to read the codes.

 

[Old Coot]

Thanks for the reply Cap't.

When it first happened I pulled off the road and took the gas cap off and looked at the gasket on it. I must confess, it was late in the day and very overcast and with my aging eyes, I did not see any issues with the cap or gasket ... I never thought to check the metal sealing surface in the tank neck. It is a good idea though. Thanks for the tip! I will keep you posted on what I find.

 

[Old Coot]

Well, I had decent light this morning and looked at the gas cap gasket again and it looks good. I also ran my finger over the sealing area on the tank neck and felt nothing rough and looked for rust and saw none.