I have a montero sport 2001,and the check engine light came on ,I took it to auto zone they toll me to change the oxigen sensor,which I did four of them ,and the light still on after resting for about four times,please help me

It is highly unlikely that all four O2 senosors are bad. They may read codes for free but they are parts people not automotive technicians. Parts people just want to sell you parts. A good technician wants to properly diagnose the problem and sell you the parts you need to fix that problem.

I assume your check engine light is on and they read codes. What where the codes?

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This has nothing to do with you O2 sensor. You have more than one problem. An O2 sensor will not cause what you just described. It will cause a check engine light but not the dimming of lights and a stalling issue. Check your charging sytem ( battery and alternator )

Sounds like your alternator is not charging your battery.

must have a bad o2 sensor need to check with a scanner auto zone and advance auto parts do it for free.

could be any number of break problems, it is just telling you that the breaks need checking and before something fails.

YES. but the dealer should have been able to tell which one was bad. I would say they replaced the wrong one, having more than 1 bad is really rare.

Remove the negative cable from your battery and wait 1 hour the car computer will reset, be carefful that your radio is not anti device, otherwise you would need the code to reset your radio which is a four number code.

Good Luck!

The Cat code could have cleared itself if the computer doesn't detect a problem anymore. Fix the EGR problem as it is still active.

my 1998 Montero Sport has 4

when your vehical throws a code and you replace the defective part, you must clear the code or the ecm will still recognize it as an active code.