We read error code 4011 with the check engine light on. Is this something we can fix? And how much is the estimated repair cost?
Take it to the local auto parts store and have them pull the code and print out what the code is and what it means. advance, autozone, etc will do this for free.
DO NOT buy any parts yet. post what the code is here so we can try and help you figure out what the problem is.
One code was P0411, and two more, all relating to the secondary air pressure switch. I can get the other two codes this afternoon, our printout is on the counter at home.
What engine do you have? It looks like I6 is only option for '06 but you never know.
With the earlier versions on I6, the secondary A.I.R. valves were known problems. I fixed mine ('04) twice before being forced to replace it about two years ago. No problems since. Easy to change if that’s it and if you buy online it’s less than 1/2 the cost of the dealer.
Post the codes and it may help to narrow down the cause.
when i put in the vin, it gave me this: 4.2L V6 MPI
They used to come with either a 4.2L I6 (inline) or a V8. I never heard of a V6 in a Trailblazer but anything is possible 
If you pop the hood, it should be obvious which one you have…
well, I put the vin in the google search and it took me to a car fax site and that is where I copied the info from. I know it is 6 cyl, the top has a plastic thing that says Vortek 4200. I just drive it, my husband does the motor stuff!!!
That must be the Russian version with the K
Vortec 4.2L Atlas I6.