So my cadillac cts 2003 keeps saying check gas cap, and now the check engine light is on. I make sure my gas cap is secured(5-8 clicks). And still i keep geting check gas cap and service engine light is still on, i even bought a new gas cap but still nothing... What can it be and whats an estimate price on fixing this problem? If you know whats wrong or had an issue like mines and fixed it, please help me out. Ty

SOURCE: Cadillac Deville 2000- Engine check light code P0741

If you like go ahead and let someone sell and replace your transmission but here is my suggestion! Check around and see if you can find a minor vacuum leak! This can simply be the big round hose that goes from the fuel injection to the power brake hub! This is normally a push in connector which has about a 1/2 inch hose clamped on it! If there is any kink or the connector is not in correctly a leak will occur and the transmission will shift rough as though you will be thrown out of the vehicle! Try unplugging this connector and plug it back in hard and straight and maybe you will be lucky and fix your problem. If the vacuum is correct your transmission will shift better than you have ever experienced!

SOURCE: Anti Theft Problem

Not much you can do without an expensive scanner and wiring schematics. You can check all electrical grounds for loose or corroded connections that includes the battery. Also check all fuses. Other then that you would need to take it into a shop. I wouldn't recommend a dealership because I feel there labor rates are to high and secondly the car is old enough that any half way decent shop should be able to fix or at least diagnose the problem. Hope this helps and good luck.

SOURCE: T/C light comes on in the dash of my 03 Cadillac CTS

T/C would be traction control i would think

Robert

SOURCE: 2003 Cadillac Deville a check gas cap error appears with svc engi

put a new gas cap, those system are pres. even if
the cap look ok it maby leaking replace with a new
one it should solve your prob.
eng.ligh come on because of the gas cap

SOURCE: cadillac 2004 cts, wont start

My car just started to have this same exact problem. Worked fine, came back home from a trip and it won't start. Everything comes on but no fuel guage movement or click when try to start. I have 85,000 miles on the car. Seems to be a common trend. Anyone find or receive a fix from a dealership?