I bought a 2000 Suburban this past weekend with high mileage. The Service engine light came on. Took it to a shop and they made some repairs, replaced sensors, etc. Not totally sure what all was done. It came back on. I watched the mechanic do something like turn the ignition switch to run and then back off several times in order to clear the light and was wondering if somone could tell me what the trick was.

No such thing on that truck a scanner is required or the codes clear when the pcm sees no problem after a certain number of drive cycles in most cases.

I watched the mechanic do it. Drove the truck 500 miles with no light and it came back on yesterday. Wonder if I should check the gas cap???

I watched the mechanic do it. Drove the truck 500 miles with no light and it came back on yesterday. Wonder if I should check the gas cap???

What is the code(s)?

//2000CAYukon

I bought a 2000 Suburban this past weekend with high mileage. The Service engine light came on. Took it to a shop and they made some repairs, replaced sensors, etc. Not totally sure what all was done. It came back on. I watched the mechanic do something like turn the ignition switch to run and then back off several times in order to clear the light and was wondering if somone could tell me what the trick was.
First off, you should know exactly what was done to your vehicle..especially if you paid for the work.
Secondly, if your mechanic replaced components to repair a SES light and the light came back on after the repair, he didn't fix anything.
Now he is trying to hide his mistake.
Find out what he did and what he replaced, then go to Autozone and have the codes pulled.
Post the codes here and find a reputable automotive TECHNICIAN to properly diagnose and repair your vehicle.
After that, go back to the mechanic and demand your money back.

Code is P0406

P0406
Exhaust Gas Recirculation Sensor A Circuit High?