Question from Canada. I had a check engine light that indicated a bad front o2 sensor (estimate $406.00 for the part, 200.00 for labour). I have purchased an NTK 25629 front 02 sensor and have had it installed. This is the correct part according to the parts supplier. However, the check engine light comes back on after it has been reset. Has anyone had similar problems with after market o2 sensors? My car is a 2003 2.4 non-turbo S60.

 

NTK is a great alternative to Bosch or OEM volvo. In fact, the only time I will buy Bosch is if its cheaper than NTK.

Quick solutions. Replace spark plugs (if fouled). Inspect ignition coils. Replace air filter (if overdue, dirty). Clean MAF (only after replacing filter). Reset CEL.

 

Sure it was the front O2 sensor and not the rear one??
What exactly did the code say??

 

no code will point you directly to the problem, sometimes testing will point you to repair the part mentioned. depending on the code- like system lean or system rich, you may have a vacuum leak or a leaky injector...

 

The code said: bank 1 sensor 1

 

there would have been more than that in the decription, do you know what number it was? example- P0101. with the code number you can research specific diagnostic procedures. all of our cars will only have a bank 1- that refers to one side of the engine or the other, but in a inline engine there is only 1 bank. sensor 1 would refer to the sensor before the catalytic converter but is the sensor that measures the air/fuel ratio coming out of the engine. meaning the code could be telling you that you are running rich(too much fuel) or lean(too little). sometimes it will also mean that the sensor is bad, or a broken wire, or even the PCM has an issue. sometimes you get lucky by throwing a new sensor at it, sometimes not.