Difference in NOx/Oxygen sensors

zagg · Mar 19, 2015

I'm in need fo replacing my front NOx sensor. In perusing the web and such looking for the sensor I am wondering what is the real difference between the two (the front and back sensor). They are all really oxygen sensors based off the Nernst Cell principle. The difference alone may be in the coding of the control module for the sensor, or not, OR the difference may just be in the length of cord from the sensor itself to the control module. Don't know. I know on my 01 Jeep GC the only difference between Bank 1 and Bank 2 oxygen sensors was the cord length and like $5.

In reading up on the sensors many say that they are for the before or after the oxidative catalyst. OK, but in the end the fore or aft NOx sensor is still only gonna sense NOx. And in looking at the physical appearance of the fore and aft sensors I see no difference.

The part # for a new replacement sensor is 059-907-807H. I found a 059-907-807D used for half the price. Unless the sensor cord is drastically shorter I see no reason why it should not work.

Anyone else have some experience here?

nikoloz · Mar 19, 2015

hey Zagg how are you doing

i can explain it but forgive me if im not using correct words for it as im not the native English speaker, the first sensor that is before the cats are measuring how effectively fuel was burned is it Lean/rich and sensor that is after the cats are measuring how the cats have cleaned the exhaust gasses and if it is doing the job as it should

hope this helps,

nikoloz · Mar 19, 2015

so basically first sensor is an O2 sensor that measures if there is any left over oxygen in the exhaust gasses or lack of it and then it sends this info to ECU and the ECU is calculating the right mixture ratio to make the engine more efficient so it will add more/less fuel so that the air and fuel ratio is always bang on around 14,7 as far as i know

and the second sensors are measuring if the cats have done their job, it also is connected to ECU and create a loop

hope this helps

zagg · Mar 19, 2015

Hey Nikoloz.....I get what each sensor is doing and why it is where it is in the exhaust. But, as far as the sensor itself I do not see how the front NOx/oxygen senor is physically any different than the rear sensor. From my understanding they are exactly the same as far as physical design, composition and both function by the Nernst cell principle. All NOx/oxygen sensors do.

Now, as far as what they actually detect/sense NOx/oxygen concentration wise are two different things as is the signal they send back to the ECU in proportion to the amount of NOx/oxygen they are detecting. Isn't it the ECU and the parameters of the emissions program that set the detection parameters/limits/ranges for NOx and oxygen content and not the sensor. The senor is merely a device for quantitating the amount of NOx/oxygen in the exhaust and sending the appropriate response to the ECU proportionate to what is being detected.

nikoloz · Mar 19, 2015

off course the sensor is only detecting and all the rest is done by EMS (engine management system) thats why if someone will remove those sensors or not change them in time and be running without them cats go crazy and blocked up and you will never pass emissions test

and will never have good MPG

zagg · Mar 20, 2015

nikoloz said:
off course the sensor is only detecting and all the rest is done by EMS (engine management system) thats why if someone will remove those sensors or not change them in time and be running without them cats go crazy and blocked up and you will never pass emissions test and will never have good MPG

Thanks, that's what I thought. Just needed some support for my thinking

nikoloz · Mar 20, 2015

zagg said:
Thanks, that's what I thought. Just needed some support for my thinking

yes i know that feeling

now this might and will sound ridiculous but lot of idiots do take hole catalytic converters out here in Georgia as at the moment we do not have to pass any inspection, its stupid and horrible, lot of old cars on the road and dirty air in capital, most of the cars are running with messed up exhaust system and CEL on all the time

this is sad trues here

mickmackinbiker · Mar 20, 2015

zagg said:
I'm in need fo replacing my front NOx sensor. In perusing the web and such looking for the sensor I am wondering what is the real difference between the two (the front and back sensor). They are all really oxygen sensors based off the Nernst Cell principle. The difference alone may be in the coding of the control module for the sensor, or not, OR the difference may just be in the length of cord from the sensor itself to the control module. Don't know. I know on my 01 Jeep GC the only difference between Bank 1 and Bank 2 oxygen sensors was the cord length and like $5. In reading up on the sensors many say that they are for the before or after the oxidative catalyst. OK, but in the end the fore or aft NOx sensor is still only gonna sense NOx. And in looking at the physical appearance of the fore and aft sensors I see no difference. The part # for a new replacement sensor is 059-907-807H. I found a 059-907-807D used for half the price. Unless the sensor cord is drastically shorter I see no reason why it should not work. Anyone else have some experience here?

Hi Zagg, something else to keep in mind is sensor range when comparing. Yes, there may be external differences, but there may also be internal differences.

Right now I have no experience with what slight differences in a VW part number mean. A different P/N may indicate a change up.

A person may get errors when installing a different sensor due to the ECM not getting information within the range it is programmed for.

Comparing two sensors with a multi meter may show similarities but not the whole picture.

Give it a try. The worst is you will have to replace it with the correct part!

Mick

zagg · Mar 24, 2015

Installed part 059-907-807D, rear NOx sensor and control unit from/for a Q7, cleared code and MIL light has stayed off. The only difference was length of sensor cord. 059-907-807D was cord was 6 inches longer than 059-907-807H

mickmackinbiker · Mar 24, 2015

zagg said:
Installed part 059-907-807D, rear NOx sensor and control unit from/for a Q7, cleared code and MIL light has stayed off. The only difference was length of sensor cord. 059-907-807D was cord was 6 inches longer than 059-907-807H

Glad to hear the sensor R&I was successful! Good information to archive.

My plan is to change all the sensors when I install Les's pipe kit. I have had an intermittent Bank 1 sensor fault throughout this winter. Adblue glitches as well. All problems seem related to extreme cold; as it has warmed, problems seem to have subsided.

Mick

bat0nas · Oct 6, 2015

Hi,

So what is the difference between letters at the end of the part number?
I have second hand 2011 V6 3.0 TDI.

Here's a photo of the front sensor. You can see that it's "G" and made in 2013. So it was definitely replaced recently

What is the original part number of the 2011 touareg NOx sensor?
Thanks!!!

nikoloz · Oct 6, 2015

Is this the cabin oxygen sensor? Cause in the thread we were discussing oxygen and NOx sensors that are in the exhaust system before and after the catalytic converters

That sensor looks like cabin oxygen sensor

Njord · Oct 6, 2015

bat0nas said:
Hi,

So what is the difference between letters at the end of the part number?
I have second hand 2011 V6 3.0 TDI.

Here's a photo of the front sensor. You can see that it's "G" and made in 2013. So it was definitely replaced recently

What is the original part number of the 2011 touareg NOx sensor?
Thanks!!!

That is the original part number 059907807G. Control unit with "NOx sensor". Letter G means "behind catalyst". Expensive box

bat0nas · Oct 6, 2015

Njord said:
That is the part number 059907807G. Control unit with "NOx sensor". Letter G means for the car equipped with catalyst.

Could you provide source for this information (that G = catalyst).
Because I can't find any control modules on the internet with G letter which would be manufactured earlier than 2013.

For instance:
https://www.ecstuning.com/ES2639820/
You can find:

Previous Revisions 8K0907807 059907807B 059907807D 059907807F

Looks like - lower letter = older part. But all of the are the same.

You can see the same in this video (Audi Q): [ame]https://youtu.be/ngDDSIGnp-I?t=8m47s[/ame]
The guy assumes that letters changes because part is being enhanced. But they are still compatible.

So can I use 059907807D (I can find them cheap).

Njord · Oct 6, 2015

bat0nas said:
Could you provide source for this information (that G = catalyst).
Because I can't find any control modules on the internet with G letter which would be manufactured earlier than 2013.

For instance:
https://www.ecstuning.com/ES2639820/
You can find:

Looks like - lower letter = older part. But all of the are the same.

You can see the same in this video (Audi Q): https://youtu.be/ngDDSIGnp-I?t=8m47s
The guy assumes that letters changes because part is being enhanced. But they are still compatible.

So can I use 059907807D (I can find them cheap).

Sorry, I missed you asked a year sensitive number, yes, letter D is for you (2011-2012).

Njord · Oct 6, 2015

Just a newbie question. Knowing how unreliable/unstable the portable gas meters and fixed gas detection systems sensors are, how limited their lifespan is, how sluggish their response is, I wonder what sort of erroneous reading all that automotive NOx, O2 sensors provide. May be its a space/high end technology? Presumably any type of sensor frequently wander off zero and span calibrations and needs a regular check.

bat0nas · Oct 12, 2015

Njord said:
Sorry, I missed you asked a year sensitive number, yes, letter D is for you (2011-2012).

How to be 100% sure that part number with D will work?
Can't find anywhere.

Also: are both sensors identical? And should they be identical? For instance in front I have G and in that rear I would install the part with D at the end of the part number.

Thanks.

Njord · Oct 12, 2015

bat0nas said:
How to be 100% sure that part number with D will work?

If you got a non-refundable offer, for the sake of good order, I would recommend you first to consult an expert/VW dealer (because this spare part is not cheap). Or wait until someone else re-confirm my info. But I guess nobody here will guarantee 100%. The entire risk is always with you. (Actually I see no quotations for "D", only the part with trailing "G" is available, may be they are really interchangeable).

bat0nas said:
Also: are both sensors identical? And should they be identical? For instance in front I have G and in that rear I would install the part with D at the end of the part number.

It seems you should have 8K0907807D sensor before catalyst converter according to the sketch (may be 059907807G one fitted by mistake?). Again, liaise with specialists. Good luck!

noobytoogy · Oct 12, 2015

My understanding of VW parts system is that the suffix letter indicates the part has been updated or the supplier has changed but it is the same part.

Parts start with no suffix letter and then go through A, B, C, . . .

bat0nas · Oct 14, 2015

Specialists and replacement part sellers tell me different opinions. But all agree that G is OK. But nobody knows what was the original part number.

LAST QUESTION:

Could anybody (with the Treg 2011-2012) spend 5 minutes and check theirs NOx sensor part number. It's really easy:
1. Open engine cover
2. Unscrew two screws
3. Take a photo of the back side
Like I did here: http://www.clubtouareg.com/forums/f93/difference-in-nox-oxygen-sensors-198081-2.html#post1325730

It will really take 5 minutes. Thanks in advance.

This will give me enough confidence before making an order.

THANKS!!!

Difference in NOx/Oxygen sensors

zagg

nikoloz

nikoloz

zagg

nikoloz

zagg

nikoloz

mickmackinbiker

zagg

mickmackinbiker

bat0nas

nikoloz

Njord

bat0nas

Njord

Njord

bat0nas

Njord

noobytoogy

bat0nas

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