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+--- Thema: Lambda sensor bad? (/thread-42098.html)
RE: Lambda sensor bad? - ronenfe - 11.09.2020
Unfortunately this is the message of cool driver. i don't know why it shows as part of my message. I could only measure 1.4 volt with the multimeter on idle. My osciloscope got burned.
RE: Lambda sensor bad? - Broadcasttechniker - 11.09.2020
1,4 Volt ist ein (Mess)Fehler.
Selbst mit super super hyper rich bekommt man den Wert nicht hin.
Denke dran dass bei 4Draht-Sonden nicht gegen Masse gemessen werden soll.
Was ist bei deinem Scope kaputt gegangen?
Versorgung verpolt?
RE: Lambda sensor bad? - cooldriver - 11.09.2020
3 Draht, Signalmasse über Abgasrohr zur Batterie.
RE: Lambda sensor bad? - Broadcasttechniker - 11.09.2020
Immer noch ein Messfehler, 1,4Volt bekommt man nicht hin.
RE: Lambda sensor bad? - ronenfe - 11.09.2020
It's 2 wires. Signal and ground. I tested voltage between signal and battery ground. Maybe the multimeter can't measure this ac correctly but that's what it showed on different scales. There is a burned smell in this circuit of the scope. Maybe one of the chips burned. They don't sell a replacement board and it is only about 20 dollars complete so I don't bother
![[Bild: twingo-11215049-ibM.jpg]](https://pics.twingotuningforum.de/pics/2020/09/twingo-11215049-ibM.jpg)
It doesn't show any signal.
RE: Lambda sensor bad? - Broadcasttechniker - 11.09.2020
Wenn es verbrannt riecht dann suche die verbrannte Stelle.
Mit ein bisschen Glück ist es nur eine Masse Leiterbahn.
Ein "gerne" gemachter Fehler:
Das Scope wird aus dem Bordnetz gespeist und dann kommt man mit der Masseleitung auf Plus, z.B. die Heizung der Lambdasonde so vorhanden.
Dann brennt im Scope eine Leiterbahn oder ein Draht durch.
Häufig passiert der Elektronik selber nichts.
Schau nochmal.
RE: Lambda sensor bad? - ronenfe - 12.09.2020
I found a torn wire at the top of this circuit. But the display connector got broken too, so no hope for it.
RE: Lambda sensor bad? - ronenfe - 12.09.2020
Here is the measurement: https://youtu.be/PvtS2pI39PI I will try later with new battery for the multimeter.
When using clip with engine off, the clip shows about 0.5v however. I don't know why it would show voltage at all when engine is not running. Unfortunately my clip doesn't work when engine is running. I think I will buy another clip.
RE: Lambda sensor bad? - Broadcasttechniker - 12.09.2020
0,5 Volt ist ein Ersatzwert der angezeigt wird wenn kein Signal verfügbar ist.
ignoriere das. Gleiches hast du wenn du die Stecker der Temperatursensoren abziehst.
Dass die Messegerätebatterie leer ist ist ein (zusätzliches) Problem.
RE: Lambda sensor bad? - cooldriver - 12.09.2020
Ladespannung zu gering, Batterieanschlüsse korrodiert.
Deswegen scheitert er ständig. Zu wenig Wissen.
RE: Lambda sensor bad? - ronenfe - 12.09.2020
I don't think so. It was always charging like that and passed tests with no issues. Only co emission failed sometimes and passed after putting a cleaning agent in the fuel system.
RE: Lambda sensor bad? - ronenfe - 12.09.2020
Some more observations after changing the multimeter battery.
The battery charging voltage is 14 when ac off and 13.6 when ac on. Is that still a problem?
The o2 sensor still has 1.3 volt when connected to the ecu.
When disconnected from the ecu, I get more reasonable voltage. it's low on idle, when increasing engine speed it rises to about 0.8 and falls again.
See here:
https://www.youtube.com/watch?v=jHXghg1Gx7g
You are right cooldriver about low charge. I will replace the alternator brushes soon. This alternator has probably done 290 K KM.
RE: Lambda sensor bad? - ronenfe - 12.09.2020
At least I can use the xr25pc to see some data, either it doesn't show correct temperatures for the coolant sensor and air temp sensor, or something is totally wrong with my ecu connections or sensors.
I think I will still go to the TUV tomorrow just to see what's the results now.
https://www.youtube.com/watch?v=FL6buPzzBhw
It also shows a stored short circuit for the idle speed step motor and a stored open or short circuit for the throttle position potentiometer.
RE: Lambda sensor bad? - cooldriver - 13.09.2020
Absolute pressure sensor seems to be dead.
With 2000 rpm round about 500 mbar.
RE: Lambda sensor bad? - ronenfe - 13.09.2020
I think this xr25pc doesn't work properly. The clip showed no errors. And show correct values for the temperature.