Jack Garbiec

Hello,
So I finally found the can-c connector in my car(W211 2004), I was under the impression it has the same voltages as the can-b ones. That's 4.65-11 for Can Low and 0.25-0.65 for Can High, I'm fairly sure I read it on this forum that it is the case.
Now the problem is, when I measure the voltages on the CAN-C connector, they're both 2.18-2.60 or very close to those values, there is no difference between the pins, as if it didn't have can low or high, just two pins with the same voltage. So my questions are: Does can-c not utilize the can low and high connection? What are the correct voltages for the can-c connector? And finally, am I even looking at the can-c connector, I mean the location and the green wire color seem to indicate that it is indeed a can-c connector but maybe there is a connector that just looks like the can-c one.

For those curious, I'm attempting to sniff the can bus messages(using arduino and a can shield), hence my questions.

Plutoe

Most of your reference material is faulty. The system you are trying to putz or interrogate is very complicated and I am not going to provide or post the can bus specs when you can do all that yourself on your nickel---Then spend some time on how MB uses those specs in their vehicle communication.


If you have a friend with DAS Xentry have him connect and view your CAN bus with SDscan--you will learn much more with an established diagnostic tool vs open source hardware and software.

kidturbo

Do a google search for CANBUS Triple. Similar to the arduino shield setup. You'll find all my notes from hacking this W211 network posted under a forum there related to that device. Some stuff I posted over here, but mostly related to the low speed network issue which is bit tricky to get onto.

Off the top of my head, it's a 500kbs network. Which you can jack into it in drivers rocker panel. Green & Green White wires. Can-B low speed is brown / red wires.

Do proceed with caution and do some reading first... The SAM and central gateway modules become very unhappy if you start screwing around their data or bus voltage. Like will have to power down the car for 10 minutes to recover.. Engine and trans are very forgiving at least.

Good luck.

iwl

Can C is Highspeed Can 500 kbps, different to Can B Low Speed Can 83 kbps with your mentioned levels.

Highspeed Can is terminated with 120 Ohm between CanHi/Lo Line endings so level between is 0 Volt when dormant (idle), active it is +2 Volt or less depending on load between CanHi/Lo, level against ground is 2,5 Volts in the middle.

Manvinpac06

i have a w211 06 E350 with no communication found driver side under the carpet can bus C and can bus B pin connector has not been touched in 16 year that i know of remove connector's from resister should i say adjusted connector to hold the pin tighter communication is back and no ESP,ABS lights and shifter lock in park is Gone bought a breakout box to check or test the can bus high & low they are staying at about 2.5 volts with no communication with all module having no fault codes thank you guys for all the information to figure this out