Ok I've got a faulty downstream o2 sensor so I got a new one and installed it. I then reseted my Ecu and the check engine light went off..... But a few days later it came back on and was giving me the same code..... What can be wrong? The o2 sensor is new but why I keep getting the code saying its the problem? Help

 

OEM sensor or aftermarket?

 

^^^ On the right track.

If you bought one of the universal O2 sensors from like Autozone/Oreilly's/Pepboys/etc it will throw a code. The only way to remedy it, is to buy OEM from a stealership.

 

It's a Denso brand... But they should work right? It hook right on

 

Is the wiring intact upstream of the sensor?

 

I'm not sure, I just replace the downstream sensor and hook it up

 

So I bought an after market O2 Sensor as well. Except it worked for 2 months now the CEL is showing up again -_-