I have a Hyundai accent 2002, the red light "check engine" is always on, nevertheless, the car works good, not get overheat or oil consumption, so what is wrong there?

check see if cooling fan running could have faulty cooling fan relay or fuse.if cooling fan dont run when ac on car will overheat.AC COMPRESSOR PUT LOAD ON ENGINE.

This is a social web site, like facebook,so no prices

The only way to get a price is to have the motor
at an engine shop & apart,for quote or guess
at the cost of necessary repairs or a compete
already rebuilt engine replacement

the check engine light comes on to alert you that there is a problem with an engine sensor, a system that the computer monitors, or a part/system that the computer controls. There are literally hundreds of possibilities as to what could be wrong.

The best thing to do is have the computer scanned. There are a couple of options to do this.

1. A basic code reader can be purchased for about $50. This will allow you to pull OBDII specific codes.

2. Most parts store will pull trouble codes, sometimes for free.

3. You can bring your vehicle into a shop to have them run a diagnosis. There is usually a charge for this service.

Once you know what the code or codes are post them and I'll be happy to help you further.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

Look for air bleeds, sounds like the coolant has air pockets. And ALWAYS check coolent level with heater set to full heat, or water valves would be closed, and blocking coolant...

check battery voltage,check all leads are clean

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.

Gheck your oil level..If it's okay, have the oil pressure sending unit replaced.

valve cover gasket is leaking replace

HI

I think the cause can be a poor grounding connection in engine
that cause the (Oil,battery,door and hand brake lights all go on)
and no check engine light because of the (ECU) not work good
depending of no power in it because the poor ground ??

send more details after test to have more help

WITH MY BEST WISHES

SAE 10W-40
3.3 LITRES
But dont know if semi or fully synthetic
ask at local dealer or motor factors when you buy