I have 03 Yukon Denali XL. When I drive longer than an hour on highway all of sudden all the warnig lights comes on, goes off a minuite later after 2 seconds black out. Reapeats same problem every 3 to 5 minuites, once it happen.

check oil level low or no oil causes no start so does --your oil sender may have failed --oil sender also has a screen filter which causes low or no pressure =oil pump problem ==the truck wont start or may start and shut off immediately

throttle position sensor is prob. bad. unfortunately this mean replacing the throttle body

I'll try to help, everytime something gets replaced on these yukons, that circuit needs to be RESET ! Is there a reset button, on your steering wheel, to reset a variety of functions ? , check owners manual, or call your dealer for better advise

03 ,is the computer bolted to the engine around the inlet manifold area ? is it a siemans ? if so then this is your problem ,sorry never seen this vahicle here in europe but if its a similar engine to the europeon vehicle then it could be the problem but knowing american motors is most likely got a 5 litre or something

03 denalis do not have one, Gm discontinued them in 03,

i have an 03 yukon and i just replaced the fuel pump and it ran for 2 hours then it just died on the highway. it turns over but will not start. whats wrong with it???

check the head light relay int he engine compartment and the fuse to, if both these are OK then the switch is defective, the switch draws high amperage when operating the fog lamps and head lights. Buy the GM or Del-co switch. you can go to this web site to get recall info on this car as well they list parts prices as well.
http://shop.advanceautoparts.com/webapp/wcs/stores/servlet/subcategory_Lighting_-49997541_-49997588_10151_10051_-1___#storeId=10151&langId=-1&catalogId=10051&categoryId=-49997541&searchTerm=&pageId=ajaxPartList&category=&keywords=Lighting&l1_categoryId=&l2_categoryId=-49997588*-49997541&partType=&facetFields=mfrName_exact%2CpriceBucket%2Cclearance%2Csale%2C&beginIndex=0&filterValue=part_type%3A%22Accessories*Lighting*Driving+Light+-+Universal%22%7CAccessories*Lighting*Driving+Light+-+Universal&sortBy=0&pageSize=20&filters=part_type%3AAccessories*Lighting*Driving+Light+-+Universal

my 2000 yukon has the traction control light on and the abs light on any anwsers?

Had the same problem on our 03 yukon (not the changer but the main head unit) - have a 3rd party waranty and they replaced it. You can get the part for less than 300$ and it's easy to install.

Yup - you may need to get the grilles and such as well...