Hello, Is been sick of my CEL Flash. I get the code is O2 Sensor #1. So I just replaced working fine used sensor from my friend's car. But still get the CEL flash. So I try to find the causes one by one. There will be two possibilities which is the O2 sensor or the harness wire need to replace. So 1st, how do I test the O2 sensor through the 4 wires by using multimeter? and how I determine the harness wire problem? Thank You

 

Did you reset the ecu after you swapped them?

 

Yes, I did unplug the negative battery to reset ECU. But no luck still flash the CEL code O2 sensor #1 after a few miles driving. So how to back probe ans test by using multimeter? Thank You

 

You MUST provide all pertinent information about your car and engine. Failure to do so may result in thread closure.

 

I'm sorry, My engine is B-series b16b, the harness I'm using is the B16a obd1. Everything work perfectly before I change my JDM ITR 4-2-1 to JDM ITR 4-1 header. Could it be the cable harness problem?