MembersPage/VasilisP/WideBandDiagnose (2015-09-04 06:47:10)

Wideband O2 related subpage of MembersPage/VasilisP

New ECU (v3/10581 AAN with NTC MAT input, oid 10875); config file uploaded as requested in the order comment (without any change => config not changed in any way; the LSU4.2/LSU4.9 option was not changed, the paper provided with any LSU4.9 sensor instructs to check that 4.9 is configured).

Please note that [ECU with motronic55] (the controller contains the 27k nernstpullup and is compatible with both LSU4.2 and LSU4.9) can be ordered with accessories:

It would be really great if you could finally report correctly if you are actually using LSU4.9 or LSU4.2 ... Otherwise debugging your "wideband problem" is a giant waste of time; for the ECU that (you said) "will not run the car", while it is actually running in the logs.

If you purchase LSU4.2 sensor (because you prefer that), and write "please include small loom for AAN SSC5-LSU4.2" in the order comment, we'll include the loom for no extra charge: that allows to use new fw or reproduce the old setup (1.2.11 fw, config) with old fw which is not LSU4.9 certified.


Upload ini file - note: VT ini-s must be uptodate

When using new fw (eg. 1.2.31), VT must have all the new ini-s for it (preferrably the latest).

  • When i say UPDATED i mean the VE tables which were last known to work. the HTA 12A config i asked you to use in order for the car to run propeply i expected you would have had the WBO2 4.9 checked, as the ECU comes with that WB sensor and not the old 4.2 which was in the config. I noticed that myself.
Sorry about that: indeed the config file was uploaded exactly as requested without any change; would have been kind to change config for LSU4.9 (ECUs are tested during manufacturing; packaging is separate step: the sensor, paper and small SSC5-LSU4.9 loom is included in the pack during packaging).

The 'update' was on VE and lamda tables that i had reviewed myself after recent checks.

Cool, thanks.

Before the engine starts with the key turned to the pre-ignition state, my rev meter jumps to above 2000rpm and my dash warning lights up the LOW OIL LEVEL. Both stay up unless i start the car.

I have only connected the WBO2 sensor and nothing more.


Injectors=... cc/min, type=... Fuel pressure= ... bar above MAP pressure

I noticed that all my map was too rich (ECU-s nowadays come with 1.2.31 fw, but in oid10875 order comment ancient 1.2.11 config was specified, and uploaded accordingly).


Because of contradicting info if LSU4.9 or LSU4.2 is used, WBO2 setup stalled (argh, is this for real ?)

LSU4.9 setting below - if actually using LSU4.2 sensor, the mess / speculation (about sensor being over-sensitive) below just caused by the wrong main setting,

After changing the wide band setting to match the LSU4.9 sensor and tried to recalibrate, it went to 255 for me to have 20.1 at air.

Ahh OK, so actually very close. As a car owner, if got absolutely certain about LSU4.9 type, keep the 255 config value. (and if you really care, compensate for the over-sensitive LSU4.9 sensor with lambdatarget=0.89 where 0.88 intended; 1.00 where 1.00)

  • i am a car owner, and im afraid i have no means to measure what you ask. I can only tune the ECU.
  • OK. Although an Ohm measurement is the simplest thing that comes up during install (verifying injectors, igncoils, CLT/MAT sensors, WBO2 sensors, wires, all routine part of install+tune - even with a factory ECU if it comes to real-life diagnostic ). Anyway, glad to here you can tune the ECU, because that solves it all: you should be able to tune it as you wish.
  • do you have another sensor (LSU4.9 or LSU4.2)?
  • I have a 4.2 lambda sensor lightly used. If i am to recalibrate should i clean it?
No, any attempt to clean the sensor could possibly damage it.
  • is it possible the sensor was dropped (eg. to concrete floor) ?
  • SENSOR WAS NOT DROPPED!!!!
lambdatarget (=lambda reading) desired lambda (real lambda)
LR LR, or LR-0.01 below 0.9
0.79 0.78
0.80 0.79
0.81 0.80
0.82 0.81
0.83 0.82
0.84 0.83
0.85 0.84
0.86 0.85
0.87 0.86
0.88 0.87
0.89 0.88
0.90 0.90
0.91 0.91
0.92 0.92
0.93 0.93
0.94 0.94
0.95 0.95
0.96 0.96
0.97 0.97
0.98 0.98
0.99 0.99
1.00 1.00
1.01 1.01

(some multiply with zzz constant and say "AFR" that is even more unnatural).

Unless any followup info, use that -0.01 under 0.9 lambda formula to compensate the miscalibration (255 instead of 258) for the sensor apparently living on the extreme (RCal) end of the Bosch-LSU4 calibration Gaussian-distribution (being very sensitive, interestingly, so lower Ip current was needed at 20.9% O2.

Any air pressure, elevation, humidity data perhaps ? Would only be useful with Rcal Ohm data though)

  • it does not even prevent closed loop feedback EGO/lambda mixture control. VT can be configured to compensate, or another sensor can be used of course.

I am now using my old VEMS and i can send this unit back for all necessary checks.

It can be tuned where the engine is.

Maybe send the sensor if anything (but not before measuring Rcal).

I also tried 1.2.30 version without any success.

That is no surprise, as 1.2.30 works exactly as configured just like 1.2.31 (it's just that 1.2.31 has some new convenience and trigger features).

The key to success is measurements (even if just a few and simple in this case, they are important).

What can be wrong ?

If you publish the required (basic) measurements, and still not diagnosed the issue (which, with the vemslogs, seems to be rather misunderstanding or bubble), then we'll send you LSU4.9 if necessary (a sensor that we might pre-test for you).

Besides the measurement, write the SSC5 pin number and the wire color for each pin (and the wire-color at the LSU4.9 sensor !), and verify connectivity and pin-correctness of the small SSC5-LSU4.9 loom according to the [LSU4.9 pdf].

Refused to measure, but most likely all should be fine... It seems it's just the actual LSU4.9 sensor is at the most sensitive extreme end of the Bosch Rcal calibration Gauss-distribution (wbo2 calibration ~258..259 not 255; Rcal maybe ~226 Ohm ?).

"there is no attachment of .2 or .9 on the invoice and i dont understand why"

Because it is IRRELEVANT for the invoice. Logic dictates that the installer looks at the real sensor (not the invoice, which is not involved in the circuit !) and configures accordingly.

Why do you need 2 ECU for the same engine ? Was it ordered as spare ?

Hello VasilisP,

To determine what is going on please provide a bit more information, please answer the following questions for me:

  • The first 4.9 lsu calibration (with the wrong selection on vemstune, 4.2 instead of 4.9 matching the LSU4.9 sensor received) was done with a sensor completely new. The second calibration where the 255 was reached without being able to calibrate was done after the same 4.9 sensor was used with the car idling and myself looking at the trigger with a strobe light. So basically very little use.
  • My wiring is as sent from VEMS shop:
SSC5 WBO2 color wirecolor inside sensor
1 1 black ...
2 3 thick red ...
3 4 brown ...
4 5 blue ...
5 6 thin red FILL THESE IN

Checked and verified

And found wrong ? To me it looks wrong for LSU4.9 and correct for LSU4.2 !

It seems to be made to LSU4.2 pinout (it's a miracle that it works with LSU4.9 at all)... See [aan_doc.pdf]

Are you sure ? Is it the new LSU4.9 cable with small WBO2 connector ?

  • It does

Using the provided information i will provide hints on how to proceed.

Best regards, Dave


Log review (Dave) [10581_AAN_running_Vemslogs.zip]

my conclusion everything is working as it should, no wideband problems; reviewed all logs

See FileArea (how to upload files). Generic instructions on MembersPage


Can you help us understand how the misunderstandings arise ?

"Vasilios P... from UK bought after my suggestion directly from the shop as I was away on vacation. I will support him from now on on connecting the sensors and map switching option etc."

He even ordered "VEMS motronic55" since than, with same spec, but with discount. So atm this looks exactly like:

Wether or not, wasted way too much time already with all the contradictions. Real information is absolutely required for support, misleading, contradicting ... info is not the way to go.

Answer to both parties above Marcel and Dave

Look, just to clarify (and i will be ringing later to speak to someone)

1. the ECU ordered by me ( i am not Vasilis M from Munich but Vasilis P from the UK. I have no connection to Vasilis M from munich) was meant as an upgrade to my current ECU +/- spare. My current ECU was bought from EFIExpress back in 2009.

2. I ordered the ECU with the intention to have 1.2.31 and LSU 4.9 implemented as i am very busy with 2 small children, use the car almost everyday and was hoping to make a quick swap with everything being pnp.

3. When i placed the order, by checking the link: use lsu4 on the motronic pnp vems shop page, it links to LSU4.9 so i THOUGHT if i tick the WITH LSU4 i would be getting the LSU4.9 and not 4.2. This is where the problems start, as i assume i have a new ECU with a 4.9 connector and loom all ready to be fitted. I have schematics to go with it as were included in the order. Last time i fitted the LSU4.2 was in 2009 so no i did not check the size or the cable color on vems wiki to clarify what i had been sent. This was my mistake and i do apologise for not noticing sooner as the lamda issue and clarifications could have been avoided.

I therefore have an ECU without the 27k nerst pinup and without the 4.9 lamda. As i mentioned above the 2 lamda sensors (my old one 4.2 and the one sent from VEMS are IDENTICAL, have same size connectors but have different part numbers.

4. Besides the LSU issue, the dash issue is equally important to me. I cannot accept to use this ECU with it having some kind of electronic malfunction whereas it should not as a brand new item. This OIL level warning before startup can be very confusing and will force me to regularly check for oil level in a perfectly ok engine. I find this unacceptable for a brand new ECU to be working like this and vems trying to say: sure, its ok, it wont damage anything, when it shouldnt be doing it in the first place!!!

I would therefore like the ECU to be sent back to be checked for the above fault. If it cannot be fixed id like a refund. If it can be fixed, then id like the 27k pinup included and ill buy the 4.9LSU with the loom to connect to the ECU when sent back.

thanks