O2 Sensor quick question

[gman4dx266]

2002 Chevy Impala, 3400 6cyl.

Just 2 O2's right? One back by the firewall and one after the cat, correct?

Which one would be setting P0135? Im guessing the one up front in the engine bay? Thanks guys!

[Eddie-98GTP]

Yep - 2 sensors, one in front of the cat (near the firewall) , and one behind the cat.

The P0135 is B1S1 O2 heater ckt, this is the O2 sensor hear the firewall and before the cat. It is rare that something other then a bad o2 sensor cause this code. If you want to verify it, ohm the 2 heater wires at the O2 sensor (the 2 wires are the same color - white I believe). If you have an open ckt, then it's a bad O2 sensor heater, which is in the O2 sensor.

[gman4dx266]

Thanks man, this car is tricky compared to looking at my Silverado. The o2 was working ok, but i guess it wasnt heating up in the time allotted, and set the code. I just replaced the gimp o2 for 30 something bucks so i should be good to go now. Unfortunately its a bosh POS but whatever works. lol

[Eddie-98GTP]

Don't worry about it, we install Bosch sensors all the time and so far I have not had any problems.

[gman4dx266]

LOL, you jinxed it man, or something. The Bosch I picked up from O'Reillys wasnt reading right. Instead of reading and fluctuating, it would remain 0 for 98% of the time and sometimes flash 2 or 4. So i took it back, and they're special ordering me a Delphi (denso) one. Still shouldnt be too much though...hooray for employee discounts :-)

[Eddie-98GTP]

Sorry 'bout that. We buy most of our sensors from O'Reillys - coincidence? Working for a parts store (or in my case, a shop) really saves on parts, doesn't it My employers son is a regional sales managre (I believe that's his title) for O'Reillys as well.

Anyway, I have a Denso on my car (Johnson Industries), and haven't had any problems there either - WHOOPS, maybe I shouldn't have said that!