02 sensors - engine management light on

Hi
Sorry to keep posting probably silly questions but I am a girl with no knowledge on cars and I like to learn.

My car keeps giving me trouble.
Engine management light came on now. I think it could be 02 sensors (sorry it could be oxygen sensors - I'm not sure now :dry: ). I had the same issue 2 years ago and had them replaced.
What usually happens is that the light comes on but disappears after a day.
What would happen if 02 sensors were not replaced? I mean what is their function?
Thank you!

How many is there on your car? What eng is it? If there are two, one before the Catalyst and one after the Catalyst they read the oxy contents of the gasses and use this to determine the fuel mixture. If the catalyst is blocking up or even breaking up then as you have already changed the sensors I would have thought that was the problem. You can remove the first part of the exhaust which is the Cat pipe and clean it out with a good pressure air line and shake it to see if it rattles. The first sensor is in that. The second sensor is just downstream under the car.
Don't worry about posting. We are here to help.
By the way what was the final outcome on your exhaust saga?

The sensors should last over 50k but if the engine is burning oil then they will get contaminated, using non-sensor safe RTV sealant will also contaminate the sensors. Before you do anything you need to get the codes read to determine what the fault is.

Any update Susie?

Hi sorry I didn't respond earlier. I have no excuse really. I was hoping the car would be OK but it's not
the car stalled today when I was driving to work. It starts straight away. It just keeps losing power. I seriously can't figure out what is wrong. I think I will have to take it to a garage but the management light went off again. It always comes on for a day and then disappears for ages. I figured out today that when I press break, it makes the car lose power.could this be because of the oxygen or o2 sensors? I'm fed up of putting money in the car it's so old but can't afford another right now.
Thank you for any advice. I recorded a little video if anyone is interested in seeing what happens when I press break. Haha

mickt wrote: How many is there on your car? What eng is it? If there are two, one before the Catalyst and one after the Catalyst they read the oxy contents of the gasses and use this to determine the fuel mixture. If the catalyst is blocking up or even breaking up then as you have already changed the sensors I would have thought that was the problem. You can remove the first part of the exhaust which is the Cat pipe and clean it out with a good pressure air line and shake it to see if it rattles. The first sensor is in that. The second sensor is just downstream under the car.
Don't worry about posting. We are here to help.
By the way what was the final outcome on your exhaust saga?

Ha you guys are funny. Exhaust is still an issue. Maybe I should just scrap the car?
I can get the silencer for £40 so it's not so bad just need someone to fit it cheap.
But if the car is falling apart anyway I'm not sure if there is any point me actually bothering with silencer. I love my jimny tho