Why is the check engine light is on?

The check engine light is on ?? Yes? Check the pre catalitic converter Oxygen sensor or upstream sensor. If the car has in excess of 100,000 miles it's probably bad. If it has less than 100,000 take it back to the dealer because these things have a warranty that is federally mandated for 100,000.

modern cars can go to 300+ miles,if serviced correctly,but to cut down on the likelyhood of repair bills,100 is a good limit to work to.
someone else can get good service out of your "old"car.

Here is the basic maintenance list for your Jeep:

~ Inspect lights and check tire pressure at least monthly or before & after each trail ride

~ Oil & filter change, chassis lubrication, differential and transfer-case fluids every 3,000 to 5,000 miles or 3 to 4 months - if you have recently crossed through water deep enough to submerge the centre of your hubs, replace the differential fluids as a precaution

~ Underhood belt and hose inspection every 3,000 to 5,000 miles or 3 to 4 months (every oil change)

~ Tire rotation and wheel balancing every 6,000 miles or every other oil change - driving offroad can knock wheel weights off a wheel, so you may need to have this done more frequently

~ Brake inspection every 6,000 miles or every other oil change - if you have rum brakes in the rear, ensure they are cleaned after each trail ride where you encountered deep mud/snow

~ Replace air filter every 12,000 to 24,000 miles or as indicated by inspection - dusty trails can shorten these intervals dramatically

~ Replace fuel filter every 24,000 to 100,000 miles

~ Automatic transmission service every 24,000 to 100,000 miles

~ Wheel alignment check every 12,000 to 24,000 miles or as indicated by tire wear - offroad driving can knock wheels out of alignment, so budget for an alignment every 3 months, then watch tread wear to see if it's needed

~ Cooling system flush and refill every 40,000 to 100,000 miles

~ Belt and hose replacement every 60,000 to 100,000 miles or 5 to 8 years

~ Engine timing belt replacement every 60,000 to 100,000 miles (when equipped) or 5 to 8 years

~ Air conditioning performance check annually, usually in the spring - be sure to run your A/C during the winter for brief period to ensure all hoses and valves stay lubricated and operable

second hand engine ,bewst advice here is to trade car in under the goverment scrappage scheme

This is Toyota's scheduled maintenance for the RAV4 at 100,000 miles...

Replace engine oil and oil filter 1
Rotate tires
Replace engine coolant 2
Visually inspect brake linings/drums and brake pads/discs
Applicable Footnotes:
1) Reset the oil replacement reminder (“MAINT REQD”) light after replacing engine oil, if vehicle is equipped with this light.
2) Initial replacement at 100,000 miles/120 months. Replace every 50,000 miles/60 months thereafter. Refer to "Engine Coolant" in the "Explanation of Maintenance Items" section in the back of this guide for more information.

Hello, according to Snap-On / Shopkey / General Drivers,
For your 2004 Ford Taurus:
1. Inspect Accessory Drive Belt 2. Perform Multi-Point Inspection (Recommended) 3. Replace Engine Coolant 4. Replace Engine Oil 5. Replace Engine Oil Filter 6. Replace PCV Valve 7. Replace Spark Plugs 8. Rotate Tires.
This is going by the general consensus from Snap-On tools and Ford Motor Co. Hope this helps :)

u can rest buy unless the faulty part is replaced you will have the light back on in about 30 miles
TO RESET LIGHT DISCONNECT NEGATIVE BATTERY CABLE FOR 5 MIN'S

Some cars do this as an indication they need to go to a garage to be serviced. You should have the car checked for the cause of the oil leaks.

Go get an OBDII check and it should tell you, i dont think there is any corrielation between the milage and the check engine light

Hi If you have not notice any changes in the engine performance is very posible that the oxigen sensor is defective, they last about 60,000 miles, if you have a utozone or chekers store near by they will diagnosis your car at no charge,C1....