codes and timing chain on a 2008 4 runner SR5 V6 4.0L

[chopperman]

I've had check engine, vcs, slippery when wet lights been on for about 4 years now. Got tired of dealership they replace a sensor back then for about $400 and less than a week they came on again. Service writer said bring it back in and they'd replace the sensor that controlled the other 3 cylinders and that might fix it ($400 again).
This year wife got tired of the lights so I took it to a private garage (certified mechanic) he did a code check and came up with code P0016-Crankshaft/Camshaft Position Correlation Bank 1 Sensor A. He checked Solenoid on B1 , works ok, so he changes oil and filter.
VCS and Slippery When Wet lights were on and flashing so he does a C-1201 engine control system malfunction. He said if codes come back, engine will need a timing chain. Well the lights are back, but I haven't had the codes checked again.
Can I go to Advanced Auto and have my codes checked there to save money or should I go back to mechanic and pay him to read the codes. How the heck can you tell if timing chain is that worn if you don't measure or physically feel how loose they are?
I'm tired of listening to wifey and can't blame her for her concern, she won't drive it out of town now. We don't have the big bucks to fix it right now. I used to do some mechanic work 40+ years ago, and haven't work on anything this new.
Thanks for any help, Stan

 

[djpope09]

Any auto parts store can read the codes for you for free. Do that instead of going to a mechanic.

My 4.0L has a small, rectangular cover on the timing cover that is held in place by 4 bolts. It's on the front passenger side of the engine, just above the water pump. If you open that up you will see the chain tensioner. If the chain is stretched, then the tensioner arm will be extended out pretty far. If you're not sure, then post the picture here and someone should be able to tell you if it looks normal.

If that area looks normal, then I would recommend pulling the valve covers off so you can rotate the engine a few times to see if the timing marks on the chains line up.