I have 112,000 miles and my 2000 Deville check engine light just came on.

CHECK OIL LEVELS ARE CORRECT, CHECK CHARGE IN BATTERY IF IT HAS A CHARGE LEVEL INDICATOR LIGHT ON TOP SHOULD BE GREEN

My first question would be what are the trouble codes stored in the computer ?

Have you replaced the sensor ?

I own a 2001 Sephia LS..."The O.D. off" flashing with "check engine light" didn't have a thing to do with an engine problem...it was simply a bad connection in one of the 3 plugs that plug into the back of the instrument cluster!! I removed the cluster, pulled the 3 plugs, cleaned them and put it all back together...No problems since. By the way...mine has 112,000 miles on it

YOUR LOCAL SHOPS,ARE RIGHT,IT RARELY IS A SENSOR,DEPENDING O WHAT TYPE OF WORK,YOU DO,WITH THIS TRUCK,TAKE YOUR TIME,AND,CHECK THE WIRING HARNESS,SOUNDS ELEC. TO ME,GOOD LUCK

well clear code and drive it about 50 to 100 miles to try reset the monters and see if light stay out if so go get it smog so the system that could couse this is a bad wireing harness this may be hard for you to diagnosis this system put if you want me to help you can emaile me and i will send you the hole diagnosis chartDTC P1340 ION Sensing Module Cylinder ID Fault (Cylinder Synchronization Fail)

cant do it here to big

Get it checked to see why the light is on. Regardless of miles, the engine light can come on.

SERVICE ENGINE SOON and SERVICE ENGINE NOW are 2 amber warning lights pertaining to the vehicles computers.SERVICE SOON advises you of a problem, although not an emergency should be attended to promptly. Your technician can trace the problem by accessing fault codes through the climate control panel. SERVICE NOW indicates a more severe problem which will most likely precipitate a failure / breakdown. The CHANGE OIL LIGHT indicates by time and mileage is a separate light.

Too much milage, In my opinion. You will start experiencing problems eventually.You can but a newer model truck for that amount of money. Of course you can do what you want. But Dodge is known to have constant problems with the transmission. I have experienced this with people that I know.Your vote would be appreiciated. If this helps.

you have a trouble code stored. This means the pcm has detected a problem somewhere