I bought my 2003 GMC Yukon xl denali from a wholesale dealer.. approx maybe an hour after starting the truck up for the 2nd time &(20 mins after driving off lot!!!) the check engine

Asked by Mar 22, 2015 at 08:41 PM

Question type: Maintenance & Repair

... The check engine light came on.. A few times while driving it turned off. Then came on.  
My dad did oil and spark plug change and it turned off for about 4 days. Then came back
on.. Last week I put in a fuel additive (Lucas) and after driving for five mins or so the light
turned off. Thn came back on about a day later.. I did the diagnostic thing at eurozone.
And that said it was the catalytic converter , knock sensor, and some other sensor... I've
been told that the diagnostic tool thing at autoozone screws up the vehicles codes and
isn't always accurate.. The catalytic converted costs over 500 bucks to replace so going
on auto zones word seems too much guess work and it might not fix the engine light..
Truck runs great. Very smooth.. Any suggestions?

2 Answers


how to replace a 2000 Yukon denial check engine light

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how to replace the bulb in my 2000 Yukon denali

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