Bosch LSU strange result

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victor2k
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Bosch LSU strange result

Post by victor2k »

Hello,
On a 2008 Nissan X-trail 2.0 dCI/M9R engine type with fault code P2A00 I made some measurements.
Using the reference from library for Bosch LSU 4.2,I checked the resistance of heater element:is good at 3,2-3,3 ohm,but in my case the calibration resistance was found between pin 1 and pin 5 (35,3 ohm)!
Can be a Bosch LSU 4.9 in my case?Also I can use the same principle:the Nernst voltage is aprox 0,4V and the pump current value will give the AFR?
Here is my capture:
Bosch LSU.txt
(70 Bytes) Downloaded 283 times
Best regards.

ben.martins
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Re: Bosch LSU strange result

Post by ben.martins »

Hello Victor,

I believe from what you have described you do indeed have a Bosch 4.9 LSU. I believe the Bosch part number for these is
0 258 017 025.

The 4.2 guided test will not give you correct results from this sensor and it is one that is being worked on at the moment and hopefully we can get this new guided test out to the world very soon.

Once we are giving the ok we will let you know.

Kind regards

Ben

Steve Smith
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Re: Bosch LSU strange result

Post by Steve Smith »

Hello and thank you for the post.

I have completed the LSU 4.9 Guided Tests for "Overview" similar to the LSU 4.2 which can be found here:

https://www.picoauto.com/library/traini ... gen-sensor

I have also completed a LSU 4.9 "Response Test" which is a far more rapid test as per Frank Massey's video here:
https://www.youtube.com/watch?v=UdbZfXMMTQs

The Technical Publication team here at Pico will process these tests ASAP rest assured as soon as they are scheduled

You are correct Victor, the Calibration Resister pin number configuration has changed to pins 1 and 5 with the LSU 4.9
Pins 1 and 5- Harness Linked via Breakouts
Pins 1 and 5- Harness Linked via Breakouts
Assuming the sensor to be functioning correctly:

The Nernst Cell Reference voltage should remain near stable at 450 mV regardless of engine fueling condition

The Pump cell voltage will rise and fall depending upon the level of oxygen content detected in the exhaust system.

You can still use a math channel to convert the pump cell voltage into current (as we know the value of the calibration resister) but a change of voltage relative to fueling condition will confirm the LSU 4.9 opertaion based on response time

Lambda > 1.0 (Lean) decrease in pump cell voltage, increase in current (+)
Lambda < 1.0 (Rich) increase in pump cell voltage, decrease in current (-)

I hope this helps, take care......Steve

victor2k
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Re: Bosch LSU strange result

Post by victor2k »

Hello,
Thank you for your support.
Today I made anew capture on LSU 4.9(a new one,without faults).
The heater resistor (pin 3 to pin 4 is 3,8-4 ohm).The reference resistor measured (pin 5 to pin 1 is 35,5 ohm-in circuit,to the ECU side 64,4 ohm,to the LSU side 79,2 ohm).All this values was measured at cold engine at 21*C.
Here is a captured signals from ref high,ref low,pump current and maf output.
Skoda_Yeti_2010_Diesel_20180522-0007.psdata
(2.98 MiB) Downloaded 288 times
And a new capture with the measured voltage between pin 5 and pin 1,injector current and rail pressure-more accurate than the previous(you can see enrichement,fuel-cut phase) :D
Skoda_Yeti_2010_Diesel_20180523-0003.psdata
(2.4 MiB) Downloaded 289 times
Also using VCDS to read lambda values
Skoda_Yeti_2010_Diesel_20180525-0001.jpg
This oxygen sensor is very fast :shock:

Only 100ms to detect the changing in air/fuel ratio.

victor2k
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Re: Bosch LSU strange result

Post by victor2k »

Hello again,
How can be masured Ip(this is specified in LSU 4.9 data from Bosch)?
Using this schematic
LSU 4.9&CJ125.PNG

Ia=Ip+Ipump cell...but we can measure only I trim(through trim resistor U trim/R trim) :o
Can be ignored Ipump cell ?

MarcoM
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Re: Bosch LSU strange result

Post by MarcoM »

Hi Steve, I know this is a very old post but I am having trouble getting information on the Ohms the heating element LSU 4.9 has and I can't find the guide similar to the LSU4.2 you are taking about. Could you please put a permalink or something similar?
Regards,
Marco M
Steve Smith wrote:
Thu May 24, 2018 1:40 pm
Hello and thank you for the post.

I have completed the LSU 4.9 Guided Tests for "Overview" similar to the LSU 4.2 which can be found here:

https://www.picoauto.com/library/training/testing-the-bosch-lsu-4-2-broadband-oxygen-sensor

I have also completed a LSU 4.9 "Response Test" which is a far more rapid test as per Frank Massey's video here:
https://www.youtube.com/watch?v=UdbZfXMMTQs

The Technical Publication team here at Pico will process these tests ASAP rest assured as soon as they are scheduled

You are correct Victor, the Calibration Resister pin number configuration has changed to pins 1 and 5 with the LSU 4.9

O2 sensor breakout1-Pins1-5.jpg

Assuming the sensor to be functioning correctly:

The Nernst Cell Reference voltage should remain near stable at 450 mV regardless of engine fueling condition

The Pump cell voltage will rise and fall depending upon the level of oxygen content detected in the exhaust system.

You can still use a math channel to convert the pump cell voltage into current (as we know the value of the calibration resister) but a change of voltage relative to fueling condition will confirm the LSU 4.9 opertaion based on response time

Lambda > 1.0 (Lean) decrease in pump cell voltage, increase in current (+)
Lambda < 1.0 (Rich) increase in pump cell voltage, decrease in current (-)

I hope this helps, take care......Steve

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PicoKev
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Re: Bosch LSU strange result

Post by PicoKev »

Do you not use Google?

See here

Kev.

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