eignub

So after replacing all the O2 sensors, and the catalytic converter (and front pipe just for good measure) on my 01 Sport, I am now getting P0135 and P0141 errors. To save the time of looking them up, they are O2 Sensor Heater Circuit (Bank 1 Sensor 1) and O2 Sensor Heater Circuit (Bank 1 Sensor 2). I know there is both a fuse and a relay under the hood for those circuits, but I would assume if one of those were bad, that the codes would be getting thrown for all 4 O2 sensors, not just two of them. I also thought about the grounds, but if I remember correctly, both banks use a common ground. So when I get the time, and can find my meter, I am going to check that they are getting power, ground is good, and check the resistance of the heater themselves.

Long story short, does it sound like I am on the right track, or is there something else I should be checking while looking for the multimeter? What are the chances 2 out of 4 sensors would be bad and coincidentally be on the same side?I made sure to get NTK/NGK sensors since everyone said the other brands just cause problems.

if it matters, the only other code I'm getting right now is P0455, Large Evaporative Emission Control System Leak Detected, but I do not think that would affect or cause this.

Thank you in advance.

eignub

anyone got any ideas?

CCKen

There are two relays and one fuse for the O2S heaters in the PDC. If the fuse was blown all four O2S heaters would be inop. However, if the relay that powers the Upstream O2S' was inop it may be creating your problem.


You could try swapping the AC Compressor Clutch Relay with the Upstream O2S Relay, clear the code(s) and see if they reappear. If they don't, that Upstream O2S relay should be replaced. If the code(s) reappear you may have a wiring issue.


Check the O2S ground point anyway. It's at the two studs on the right front of the engine, where the battery negative cable connects to the engine.


Edit: The O2S heaters fuse is mini fuse F17.