Thread: check engine light problems

I have been trying to clear the check for the down stream O2 sensor but the light continues to come back. I have changed the sensor, cat back, and ECU. Dont know what else to do. 1999 SE-l

Changed the front one yet? Usually the front will set the rear off.

yeah, I changed both.

Any other Codes or just that one?

no, thats all.

Well usually the Rear 02 is worthless as it just makes sure the front one is working. That's why I asked if the front one was good because they usually go hand in hand. Something else must be going on maybe the actually wiring to the 02 sensor. Maybe try to check the voltage to see if it's seeing what it needs to?

Ill check the voltage. I have sadered the wires

That could be the issues, I would cut the solder out and just crimp and heat shrink it.

I'll try that tomorrow, I just talked to my brother and he told me to check the voltage with the car running. The connector should read 12v on one wire and 5v on another. I'm going to cut the solder and crimp it. Thanks for the help, I'll let you know how it goes.

Did you get a universal sensor with 4 wires? You have your 2 heater and 1 signal and a designated ground wire. I just replaced my front OEM sensor with a Bosch universal and works great. I'm sure the back one is the same way?