I have a 2007 GMC Envoy, the engine light has been on for a while now, took it to the dealer and a code P0506, they reset the light, took my $100 and said nothing is wrong, three days later, the engine light came back on, a coworker told me I need my Throttle Body cleaned, took it to another mechanic, cleaned the Throttle Body, light went out and the next day it's on again, does this mean I need to replace the Throttle Body?

It's a short in the instrument cluster.
I had the same problem with my 2004 XUV.
It started in early December of 2007.
Intermittent manifestations, than more persistent.
Took it to the GMC Dealer --
Of course, the Truck wouldn't do it's tricks for the Tech.
They replaced the ignition switch and sent me home.
It got progressively worse.
I waited until I was sure it would do it for the tech.
Took it back in to GMC Dealer--
It's a short in the instrument cluster.
They needed to replace the entire cluster.
I bought an extended warranty when I bought the truck.
The warranty is still in effect --
So I only had to pay the $100 deductible.
No Idea what it might cost otherwise.

First have scanned for codes could be something wrong. Then fix the problem and use the code scanner to reset light

Run a diagnostic test to show what codes come up. That will identify the reason the engine light came on. It will also reset the light.

Code 506 means the engine computer can not maintain normal engine RPM at idle. Could be a problem with the idle air control valve, or something else.

Why would you be at a dealer with a 10 year old vehicle

Have extra money to throw away

How about a local repair shop

How is it you had work done & still
have any problems,what do these
shops do,half a job

{: ) DTC P0506 Idle Speed Low
The usual cause is an excessive carbon build-up on the throttle body. If this is the case, I suggest you have your throttle body cleaned and perform an idle relearn procedure using a GM scan tool. The idle relearn or reset procedure is very important, otherwise this code may still remain even after a throttle body clean.
In a similar fashion, if the ECM/PCM (engine control module) of a high mileage vehicle is replaced and/or reprogrammed without performing the Throttle/Idle Learn procedure, the ECM/PCM may no longer compensate for existing carbon build up in the throttle body, causing it to return with a similar concern as well as DTCs P0121, P0506, and/or P0507.
There are other conditions that can also affect or reduce idle speed by increasing engine load like incorrect torque converter clutch (TCC) operation, accessories that require additional torque to operate, restricted exhaust, and mechanical conditions that limit engine speed.

Hello: Without being there when the smoke test was performed no one can say what the results of the smoke test were. I would go back to the dealer and speak to the service director/service manager and request a new gas cap.

Well the first mistake you did was not take it to your GMC car dealer and let them check it out. It could be a computer problem inside the dash somewhere. Hope this helps!?

Please rate solution - Thanks.

This is a safety feature that the vehicle brings. You need to reset the E.C.U on dealership or it will keep doing it to you. It was probably caused by one single time that you did not closed the fuel cap correctly. Good luck

your check engine light is to notify you of an emission problem. your local autoparts dealer will most often check your code for free.