1998 Deville Service enginee light comes on when outside temp goes below 50's

[Rocket112]

I Got this 1998 Cadillac Deville Back in Last November from orignal owner, He said the Service engine light goes on whenever outside temp goes below 45. I had the Service engine light DX by local auto store that plugs in a gizmo under the driver side dash board. some code came up to do with a fuel O2 sensor, 2 mechnicss said , code something do with fuel mix sensor, Sometimes these sensors quirky , As long as the car is running fine and idle good Don't worry, When they were done the Service Engine light was off, I was told oh we just reset it. But came back on again as temp continue to get cold, But as Spring arrived and temps stayed above 50 regularly. I am not sure if I had reset again or not But once spring arrived and the over night low temp did not dip below 50s or 40s light did not come back on, and was fine all summer until Just recent September 24th took car out for Detail car wash etc. noticed when started car light returned back on. pass overnight temps been in the 40s the service engine light back on, I am disabled and don't drive car much but 3 to 4 times localy.
So if it is a easy thing for me to do to reset I be interested in knowing how to resset it, or is it something auto guys mechnics use to tap into cars pc? I know how to reset the oil dash monitiors and other dashboard MPH miles per gal, trip resset, One mechnice said if light bothers me put small peace black tape over the light if want, lol. thought be interesting to know how to reset it just as how to reset other dashboard monitoring instrument info. Thanks, PS; I got the car in really nice condition outside nice and inside all black leather interior very nice, I use Lexol Leather cleaner ph,and lexol leather condition. Also over the summer swithed over to been using Merguires Ggold Leather condition, apply to all the leather about every 6 weeks to keep leather soft clean w/ nice gloss look. I am only one in car most times and tio keep leather hopefully in the very nice condition got it in. Does anyone else fine these 2 products also good to switch from and or do you know of a better product that gives better results.?

[rockfangd]

I wonder if one of the o2 sensor heaters is acting up and causing your SES light, Can you give the specific code?

It is simple to pull codes on your Deville. Turn the key on (engine running or off) look at your climate controls. Press and hold the OFF and red WARMER buttons for 3 seconds. You will see everything light up and then the codes will cycle on the dash for each system. Have a pen ready to write them down.

To exit hit the recirculate button or recycle the key.

As for the leather. Mink oil works wonders.

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