2005 GMC Yukon

under the hood I would check the thermostat to make sure it open so that the hot antifreeze reaches the sensor to make the fan start

Might help, disconnect negative terminal from battery for 10 minutes, if the compute is getting weird readings this will reset it and maybe help.

Go to your local parts store,(Advance Auto, Napa, Autozone) and get the codes read for free and they can help somewhat of what the code means. If they can't tell you what the code means tell us what the code is and we can help from there.

Check engine light means, that your engine computer pick up a bad signal from one of your engine sensor, the engine will still run good because of back up sensor's,need to have a code reading done to find out what's wrong or it will damage other sensor's, you can go to any auto parts or autozone where they can do a code reading at no charge, get back to us with the code number, so we can help you diag. your trouble code.

OBD-II code P2120 What does it mean? Throttle/Pedal Position Sensor/Switch "D" Circuit

Poooooooooo2125
ThrottlP2125
ThrP2125
Throttle/Pedal Position Sensor/Switch "E"ottle/Pedal Position Sensor/Switch "E"e/Pedal Position Sensor/Switch "E"

GMC 2000 Engin code C086B what is this code it will not go away and no one can fix it

you can disconnect the battery and hopefully it isnt a hard code that comes right back or go somewhere to have it scanned for the code information and cleared so you can correct the issue

You probably have water in your fuel . Use some Stabil healthy dose and then some isopropyl alcohol gas line antifreeze that Will probably fix it . and fill it at a popular gas station , not a little station that only sells a little gas. Its either that or you might have a pluged cattalyitic converter. Try this site . http://www.obd-codes.com/forums/search.php?search_id=active_topics

engine lght is on - lack of power

Did u put in fuel shortly before the light came on? I own 2 service centers & the most common situation with "Check Engine" lights are because the fuel cap wasn't re-installed or not tightened. When you refuel make sure it "clicks" when putting back on. We don't charge for a "Code Reading" but a dealer will, don't go there. Go, like the others suggested. If it is the fuel cap & you re-install it correctly, the light will go off after a short drive. Good Luck. PS-Don't panic when the "Check Engine" light comes on unless it blinks, if that happens don't drive. PSS-RE: Murray's, Auto-Zone.......If it's a "Code" (the reader will give a #) the code book will tell you the problem. PSSS-Some1 please have Troy W's Mommy & Daddy take away his keyboard. Just because you can put together a "Lego" car doesn't make you a master mechanic. You only repeated what we said except you have a "Napoleon" complex against any1 plugging something in to a vehicle. It's the same as plugging in a light @ home. In conjunction with "kinder" nine out of ten time in my experience it usually is the oxygen sensor(s) which would be about right with the year model