P0135 Oxygen O2 Sensor Heater Circuit Malfunction

Hi, I just bought a used 2000 Tacoma and have some work to do on it. First thing is a check engine light p0135, i feel like I’m chasing a ghost, I changed both 02 sensors , the cat converter , plugs , wires and coils . Just came on again, if anyone has any advice on where to head next. That would be greatly appreciated .
Thanks

 

Check all fuses.

 

Thank you

 

It is the O2 heater circuit for the first sensor.

The wrong Sensor for application .

Poor Connection damage to plug or wiring harness to the ECM

ECM damage

 

In addition to the suggestions by @Wyoming09, I suggest checking for signs of a rich condition just in case. Sometimes codes don't always mean what they say. A rich fuel mixture will mess up O2 sensors, and it might not necessarily be "bad" enough to trigger a CEL for the rich condition. So check that your spark plugs aren't fouled, your fuel injectors are good, and your MAF is working properly. Also just do the "obvious" and check the condition of the O2 sensor. If there is carbon buildup on a fairly new sensor, you likely have a rich condition. Hope this helps.

 

@Dandentaco
2000 3.4L Tacoma was an odd year when the B1S1 Sensor may be an O2 sensor if Federal emissions are written on the emissions sticker under hood.
An Air/Fuel sensor is used if emissions stated on sticker are California.
Check your emissions sticker and use only identical OEM Denso sensors.
Link below to check #s and order

https://densoautoparts.com/find-my-part.aspx

 

The heater just is in play to the exhaust temp comes up only a few minutes.

Easy to test the O2 sensor check the incoming voltage and check if the heater coil is open

I see that plug pulled apart because the harness does not get unbolted from the top of the transmission