Code P0135 but is it O2 sensors? 03 Z71

[hendedo]

Hello All. 03 Z71, 118K miles. all stock. 5.3L, 4WD.
CEL came on, took my hand held scandevice and read P0135. My book says "02 Sensor Heater Circut Malfunction (Bank 1 Sensor1)"
Do I change all 4? If they are original ( I think they are). Shouldn't they all be replaced?
Do I disconnect the battery afterwards to 'reset' the ECU also?
Thanks for any help.

 

[biggb20042001]

I got same issue 2004 Yukon Denali. im tuning in for answers and part numbers

 

[Screwd up 6]

I would say since the code is stating "02 Sensor Heater Circuit Malfunction" it is the 02. I had this same thing on my blazer and a 02 sensor from autozone fixed it (although Id buy acdelco if you can afford the more $$). When my code was being thrown, it was hit or miss. Sometimes the light would come on, sometimes it wouldn't. It was not on every time.

From what I know, when the code is P0420 that is when people buy new 02's and it could be a number of other things therefore you are wasting your $$ by just guessing that is the problem.

Hopefully someone can chime in with more info for you.

 

[biggb20042001]

Talked to GM parts guy and he gave me some information on the part # for bank1 sensor1. The GM part # 12572705 or AC Delco # 213-1161. He says GM recommends doing both sensors #1 & #2 at the same time meaning if bank1 sensor1 goes out do both and they are the same part #s. I ordered off amazon $56.02/each dealer charges $140.52/each.