# O2 Sensor **URL:** \ **Category:** Maintenance/Repairs\ **Created:** [March 25, 2013, 5:31am UTC](https://community.cartalk.com/t/o2-sensor/78252 "2013-03-25T05:31:19Z")\ **Posts on this page:** 18\ **Page:** 1
**Author:** ![uwmad](https://avatars.discourse-cdn.com/v4/letter/u/9d8465/32.png) [@uwmad](https://community.cartalk.com/u/uwmad)\ **Post date:** [March 25, 2013, 5:31am UTC](https://community.cartalk.com/t/o2-sensor/78252/1 "2013-03-25T05:31:19Z")
I have a 2001 Nissan Maxima with a P0135 error code. My question is this a definite bank 1 sensor 1 O2 sensor or is this a generic code for any of the four 02 sensors? I want to change the correct one. Thank you very much in advance. ---
**Author:** ![shannon\_darst](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/shannon_darst/32/2606_2.png) [@shannon\_darst](https://community.cartalk.com/u/shannon_darst)\ **Post date:** [March 25, 2013, 5:38am UTC](https://community.cartalk.com/t/o2-sensor/78252/2 "2013-03-25T05:38:19Z")
take it to an autoparts place that has a code reader and that should tell you which one it is. ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [March 25, 2013, 5:46am UTC](https://community.cartalk.com/t/o2-sensor/78252/3 "2013-03-25T05:46:40Z")
The DTC indicates that the heater circuit for the O2 sensor before the catalytic converter has failed. This is usually caused from thermal shock to the O2 sensor heater circuit. Tester ---
**Author:** ![uwmad](https://avatars.discourse-cdn.com/v4/letter/u/9d8465/32.png) [@uwmad](https://community.cartalk.com/u/uwmad)\ **Post date:** [March 25, 2013, 5:47am UTC](https://community.cartalk.com/t/o2-sensor/78252/4 "2013-03-25T05:47:21Z")
The code reader read “P0135 generic bank 1 sensor 1”. I assumed it was the bank 1 sensor 1 O2 sensor, but the more I thought about it, the term generic made me wonder if this is truly the sensor I should replace. ---
**Author:** ![uwmad](https://avatars.discourse-cdn.com/v4/letter/u/9d8465/32.png) [@uwmad](https://community.cartalk.com/u/uwmad)\ **Post date:** [March 25, 2013, 5:50am UTC](https://community.cartalk.com/t/o2-sensor/78252/5 "2013-03-25T05:50:29Z")
Thank you. Tester ---
**Author:** ![Tester](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/tester/32/15976_2.png) [@Tester](https://community.cartalk.com/u/Tester)\ **Post date:** [March 25, 2013, 5:54am UTC](https://community.cartalk.com/t/o2-sensor/78252/6 "2013-03-25T05:54:29Z")
Anytime I see that code, the O2 sensor heater circuit has failed. And I replace the O2 sensor. Tester ---
**Author:** ![uwmad](https://avatars.discourse-cdn.com/v4/letter/u/9d8465/32.png) [@uwmad](https://community.cartalk.com/u/uwmad)\ **Post date:** [March 25, 2013, 6:03am UTC](https://community.cartalk.com/t/o2-sensor/78252/7 "2013-03-25T06:03:03Z")
This is the sensor I purchased but I didn’t want to change it and find out I changed the wrong one. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [March 25, 2013, 7:19pm UTC](https://community.cartalk.com/t/o2-sensor/78252/8 "2013-03-25T19:19:59Z")
The old one can be tested with an ohmmeter. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [March 25, 2013, 10:07pm UTC](https://community.cartalk.com/t/o2-sensor/78252/9 "2013-03-25T22:07:09Z")
It is the right sensor. The sensor itself is not bad, but it has a little electric heater inside it to warm it up faster so that it starts working sooner on a cold engine. The heater is not working. There is a small chance that the problem could be in the wiring to the sensor, but that is a really small chance and normally, you could see the damage if you look at the wire bundle going to the sensor. If the bundle looks good, not cut into or the insulation worn down to bare wire, then replace the sensor. BTW, this is really a pretty common problem for heated sensors when they get about that age. ---
**Author:** ![uwmad](https://avatars.discourse-cdn.com/v4/letter/u/9d8465/32.png) [@uwmad](https://community.cartalk.com/u/uwmad)\ **Post date:** [March 26, 2013, 8:25am UTC](https://community.cartalk.com/t/o2-sensor/78252/10 "2013-03-26T08:25:05Z")
Good idea on the continuity test on the O2 sensor. I forgot about this. I read about it or watched a YouTube video at some point. Thank you! ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [March 26, 2013, 10:17pm UTC](https://community.cartalk.com/t/o2-sensor/78252/11 "2013-03-26T22:17:10Z")
Continuity is not enough, the current has to fall within a specified range or it sets the code. Sometimes the issue is that as heaters get older, their resistance goes up, reducing the current flow. You may get continuity, but if it isn’t in the specified range, it won’t work. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [March 27, 2013, 7:18am UTC](https://community.cartalk.com/t/o2-sensor/78252/12 "2013-03-27T07:18:10Z")
@unwad personally I would bite the bullet and just replace the sensor at this point. You could spend hours testing current draw, resistance, voltage, etc. In my experience the only O2 sensor heater circuit DTC that wasn’t caused by a dead sensor heater was in cases where the wires had suffered rat damage. If you want to test it, here’s my advice: Check for 12V on the heater circuit wire when you initially turn on the ignition. If you’ve got 12V, replace the sensor. There should be only 1 wire that gets 12V with ignition on. If you don’t have 12V, find and repair the wiring problem. ---
**Author:** ![Big\_Marc](https://avatars.discourse-cdn.com/v4/letter/b/9d8465/32.png) [@Big\_Marc](https://community.cartalk.com/u/Big_Marc)\ **Post date:** [March 27, 2013, 8:50pm UTC](https://community.cartalk.com/t/o2-sensor/78252/13 "2013-03-27T20:50:52Z")
the code is for the heater for the upstream bank 1 sensor ,you need to trouble shut the curcuit to make sure the problem is or is not the sensor so you don’t waste your money ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [March 27, 2013, 10:36pm UTC](https://community.cartalk.com/t/o2-sensor/78252/14 "2013-03-27T22:36:50Z")
“You could spend hours testing current draw, resistance, voltage, etc.” It would take just a minute to disconnect the sensor and measure its resistance. ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [March 28, 2013, 7:10am UTC](https://community.cartalk.com/t/o2-sensor/78252/15 "2013-03-28T07:10:13Z")
@circiuitsmith I would rather just check if the heater circuit is getting 12V at ignition on. I didn’t say that I personally would spend hours testing all those things. ---
**Author:** ![keith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/keith/32/5518_2.png) [@keith](https://community.cartalk.com/u/keith)\ **Post date:** [March 28, 2013, 4:52pm UTC](https://community.cartalk.com/t/o2-sensor/78252/16 "2013-03-28T16:52:00Z")
> "It would take just a minute to disconnect the sensor and measure its resistance." What good would that do if he doesn’t know what the parameters for that resistance are? I’m sure by now he has replaced the sensor and all is well. ---
**Author:** ![circuitsmith](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/circuitsmith/32/40376_2.png) [@circuitsmith](https://community.cartalk.com/u/circuitsmith)\ **Post date:** [March 28, 2013, 9:55pm UTC](https://community.cartalk.com/t/o2-sensor/78252/17 "2013-03-28T21:55:55Z")
**“I didn’t say that I personally would spend hours testing all those things”** I didn’t say that either. **“What good would that do if he doesn’t know what the parameters for that resistance are?”** I made a simple statement, not intended to be complete instructions. How am I supposed to know what he knows? ---
**Author:** ![db4690](https://sea1.discourse-cdn.com/cartalk/user_avatar/community.cartalk.com/db4690/32/2583_2.png) [@db4690](https://community.cartalk.com/u/db4690)\ **Post date:** [March 29, 2013, 3:07am UTC](https://community.cartalk.com/t/o2-sensor/78252/18 "2013-03-29T03:07:50Z")
Okay guys. Everyone’s said their part by now, including me. I also assume OP has fixed the car and is happy again.