LSU Broadband oxygen sensor, is it a good one?

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LSU Broadband oxygen sensor, is it a good one?

Postby sigoaprendiendo » Sat Dec 27, 2014 10:32 pm

I was able to get a Broadband Oxygen sensor signal, the specs are:

* BOSCH LSU PIN Numbers.

* Code 17025.

* Type 4.9 broadband oxygen sensor.

* Auto: Fiat Stilo, 4 cylinders, TDI, year 2006.

I would like to know if it is a good or bad signal as I did not notice any obvious issues in this engine, maybe a slight lack of power by snapping throttle under load conditions but I am not sure about this as it was the first time I drove and played with this car for a while. I mean no data trouble codes showed up via my DEC SuperScan3 scanner.

This is the guy we are talking about:

Broadband sensor close up2.jpg

Broadband sensor wiring.jpg
The red lead correspond to the pin number 1 and the "missing" lead to the number 5

Sensor pinout.jpg
The 109 Ohms resistor was found between the pins number 1 and 5

I would like to upload the *.ps files to the Wave Form Library browser to contribute to the forum as I haven't seen any broadband oxygen sensor in the library but firstly I have to know how to name them; GOOD or BAD. :roll:

BOSCH O2 Wide band sensor Fiat_Stilo_2006_Diesel_[GOOD].jpg
This is the Pump cell current and the slumps shows up every time I snap throttle

As for this file you can see the Pump cell current as a math channel from channel A voltage which is hidden but you can get with the right click button on the *.ps files. According to OHM's Law this is Ip current flow calculated after measuring resistor at connector sensor. Resistor value is 109 ohms. This is a good signal I think :roll:

Here you are the Measurement cell signal:

BOSCH Wide band O2 sensor Fiat_Stilo_2006_Diesel Measuring Cell Volt_2.jpg
Measurement cell and the slumps correspond to snap throttles. Here is where I have doubts. What to expect from healthy engines, Slumps or Humps.

I am sorry as I wasn't able to get both signal together. Every time I tried to do it, both signal looked wrong, I mean voltage out of range according to the specs in internet. I think the problem is my scope as I have a 4423 model and as far as I know ground is common for all channels. Maybe I have to hook up an attenuator to every 4423 scope channel or need a 4425 oscilloscope with independent floating inputs, I am not sure at this point, please you tell me!!!

All suggestions to the questions are welcome before uploading the files to the library,

If are not already uploaded by means of the forum :roll:

Kind regards and looking forward to enlightment

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Re: LSU Broadband oxygen sensor, is it a good one?

Postby KimAndersen » Sun Dec 28, 2014 11:11 am

Hi Sigoaprendiendo

It's nice to see others try this method of measuring the wideband sensor from Bosch.

I reckon you have seen the case study that I made about this sensor and you will, if you have read the whole thread come across a point where Robski is asking about this resistor in the wideband sensor connector. Once more to clear up this thing, its the resistor inside the ECU you could use in your calculation which should be around 61.9 ohms.

And back to your question whether or not this is a good waveform capture !

Seen with my eyes, it doesn't look right.

Why, because when your not stepping on Accelerator Pedal (APP) your ampere reading should equal zero amps, which again equals with lambda 1 with one exception, that there are fault in your ECU or the wideband sensor or something related to the other sensors around the engine, which are sending false information to the ECU.

If I may suggest something, why not use the lookup table that i made for my case study, it works as long as your are sure the resistor inside the ECU are 61.9 ohms.

Try this and I will looking close to you this thread in the future. :wink:

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Re: LSU Broadband oxygen sensor, is it a good one?

Postby sigoaprendiendo » Sun Dec 28, 2014 1:13 pm

Hi Kim

Thanks for your encourage. I will take your advices, sadly this car is not in my neighbourhood but the owner is a close friend of mine.

Kind regards, enjoy christmas holidays, and blessings
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