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All,
from https://www.ducatoschrauber.de/tankgeber-tuning-ducato-250/ (german page) I noticed, that the original Ducato tank level sensor is meassuring between 100 and 300 Ohm. Might it be possible to connect it in parrallel also to the Cerbo so that the single sensor will support both, car and Cerbo?
Cheers,
luphi
1. The Cerbo measures 0-180 Ohm (EU standard) OR 240-30 Ohm (US standard)
2. Connecting one sensor to two measuring devices will properly distort the measuring.
Hello Matthias,
1. the Cerbo is able to meassure between 0 and 300 Ohm.
2. To meassure resistance, the meassuring device should have a very high internal resistance (should be valid for the car and the Cerbo)
So, yes, they will have an influence on each other but maybe it's not too much or can be compensated.
If it is not harmfull, I would give it a try.
Cheers,
Martin
1. Habe mir das Menü nie so richtig angeschaut, da ich selbst noch keine Tanksensoren verbaut habe, kenne daher nur das was im Datenblatt/Handbuch steht.
2. Wenn ich jetzt nicht völlig auf dem Schlauch stehe, wird zum Widerstand messen doch eine Spannung angelegt und der Stromfluss gemessen. Wenn jetzt zwei Messgeräte unterschiedliche Spannungen anlegen, wird das doch zwangsläufig zu Fehlmessungen führen.
Aber da bin ich zu wenig in der Messelektronik drin um das mit Sicherheit sagen zu können.
In modernen Autos läuft ja alles über den Can-Bus und da können auch scheinbar kleine Eingriffe schon zu Fehlermeldungen führen.
Da hast du wohl Recht. Wenn mit unterschiedlichen Spannungen gemessen wird, könnte das tatsächlich schlecht ausgehen. Danke für den Hinweis.
Gruß,
luphi
An idea for you to explore.
Read the original values from the vehicle can bus and use these. Probably better to ask a new question in the modifications space to see if anyone has done it or knows how to do it. Might be some programming involved.
Hello kevgermany,
thank you for the hint, will do.
Cheers,
luphi
I looked into CarPi and similar projects, but dechiphering the CAN buses spread over multiple ECUs seems to need a lot of backwards engineering ....:-(
I am also looking in this direction, but have not yet found a good solution. Maybe it could work if one splits the sensor cable and mounts a switchover to have the sensor available to EITHER the car OR the cerbo. The interesting part would be: what would the car do if the switchover is not switched back to the car when the engine is started?
Cheers,
luphi
Sounds like a good idea. When do you switch the relays? Manually or with ignition power? My only idea would be, what would happen if the relay once doesn't switch? How would the engine/control board react when there is no signal from the fuel sensor? Will it show 0%, 100% or the last level it remembers?
BTW: as I don't like cutting original wires, does by chance anybody know how the plug for the fuel sensor is named? Meaning this guy here.. 
I switch by ignition. That is fast enough, so that the sensor is back to the car before it's self tests.
During test phase, I missed to switch back, which raised an alarm, which disappeared as soon as the sensor was back to the car. Nothing was left in the fault memory.
Cheers,
luphi
