CANBUS Hell
Thread Starter
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,258
Likes: 168
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
CANBUS Hell
So if you read my ClusterF^&K'd thread, you'll see i had an issue with the car dying after a big rain storm, and the cluster being blank.
This has happened once before, before the hatch got dented.
1st time it happened car went into limp mode, dash was dark,
headlights on constant. Also had a wheel sensor go out.
So took it to the mechanic, he couldn't get a read on anything, CANBUS was
going crazy. So, he parked it in the shop over the weekend, it came back to life.
The BAS module hasn't communicated for a long time.
But everything else did, and I have used Carsoft successfully in the past.
Now, it only reads the cluster, ME, EGS (trans) OCP (not sure what that is), & DB2.
I am wondering perhaps water is leaking through the windshield, since it was replaced years ago? What else could it be? I don't notice water anywhere.
So more recently it died completely, wouldn't start or turn over.
But then after a while, and disconnected
So, what would be the process for troubleshooting the CANBUS?
I found this CANBUS analyser online.
Everything in the car works, but i can't read the modules via canbus,
and I can't clear my SRS error, since it doesn't read the Airbags which I guess means, I have no airbags!!!!
It also doesn't read the SAMS or lots of other things.
HOW CAN I GET THE MODULES TO START TALKING TO EACH OTHER?
What would be the 1st step in troubleshooting this?
Odd thing is everything seems fine except the SRS error till you hook up Carsoft or SDS.
This has happened once before, before the hatch got dented.
1st time it happened car went into limp mode, dash was dark,
headlights on constant. Also had a wheel sensor go out.
So took it to the mechanic, he couldn't get a read on anything, CANBUS was
going crazy. So, he parked it in the shop over the weekend, it came back to life.
The BAS module hasn't communicated for a long time.
But everything else did, and I have used Carsoft successfully in the past.
Now, it only reads the cluster, ME, EGS (trans) OCP (not sure what that is), & DB2.
I am wondering perhaps water is leaking through the windshield, since it was replaced years ago? What else could it be? I don't notice water anywhere.
So more recently it died completely, wouldn't start or turn over.
But then after a while, and disconnected
So, what would be the process for troubleshooting the CANBUS?
I found this CANBUS analyser online.
Everything in the car works, but i can't read the modules via canbus,
and I can't clear my SRS error, since it doesn't read the Airbags which I guess means, I have no airbags!!!!
It also doesn't read the SAMS or lots of other things.
HOW CAN I GET THE MODULES TO START TALKING TO EACH OTHER?
What would be the 1st step in troubleshooting this?
Odd thing is everything seems fine except the SRS error till you hook up Carsoft or SDS.
MBWorld Fanatic!
Joined: Dec 2005
Posts: 1,055
Likes: 50
From: SoCal. Desert
'16 E350, gone: '03 c230k
Do you have a 'decode' list of the CANBUS ID's, data link codes, and data in the messages for the Mercedes bus(es)? You're getting down into the 'bits' with this analyzer. CANBUS is the generic message format and interface protocalls for sending information - the end user defines the content of the messages, so you need the decode information for how Mercedes uses the bus.
If you do have the decode information, you need a way of tapping into the bus to monitor the message traffic. As far as getting the modules to talk to each other, you either monitor activity as the modules go about their business, or figure out how to talk to the modules from your decode information. I would imagine there are ways of initiating BIT's (built in tests) for modules, or sending a command a module is expecting to see and looking at it's response.
This is 'low level' stuff (i.e. the nitty gritty bits), and a DAS is programmed to decode/sort the low level stuff to make sense for an end user - kind of like a code reader decodes the bits and gives you the code # it sees and what that code # means.
Hope that helps...
If you do have the decode information, you need a way of tapping into the bus to monitor the message traffic. As far as getting the modules to talk to each other, you either monitor activity as the modules go about their business, or figure out how to talk to the modules from your decode information. I would imagine there are ways of initiating BIT's (built in tests) for modules, or sending a command a module is expecting to see and looking at it's response.
This is 'low level' stuff (i.e. the nitty gritty bits), and a DAS is programmed to decode/sort the low level stuff to make sense for an end user - kind of like a code reader decodes the bits and gives you the code # it sees and what that code # means.
Hope that helps...
Thread Starter
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,258
Likes: 168
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
I picked up the pn of the airbag module from Carsoft...
People say CS 7.4 is useless, actually it's pretty cool for what it is and much better than just an OBD reader, though I keep one of those in the car at all times.
PN is 0018209726
I found a couple on sale online, and here's where it's located.
Right under the center console.
Here's what it looks like. Now what?
People say CS 7.4 is useless, actually it's pretty cool for what it is and much better than just an OBD reader, though I keep one of those in the car at all times.
PN is 0018209726
I found a couple on sale online, and here's where it's located.
Right under the center console.
Here's what it looks like. Now what?
MBWorld Fanatic!
Joined: Dec 2005
Posts: 1,055
Likes: 50
From: SoCal. Desert
'16 E350, gone: '03 c230k
Looks like we were typing at the same time... If you want to talk to the module on it's lonesome, you need a way of supplying power and hooking into the bus. Then you need the id, data link codes and message format/decode information for that module. When you have that, you should be able to talk to it.
Thread Starter
MBWorld Fanatic!
Joined: Jun 2002
Posts: 7,258
Likes: 168
From: So. Oregon Coast
C230 Sport Coup + 2006 W164 ML350 + 99 Ford Escort RIP
I'm trying to clear my SRS error.
Can't talk to most of the modules in the car for diagnostics.
Until I can fix the communication issues on the CANBUS
I won't be able to fix the SRS error.
So what I'm trying to figure out is how to fix it.
Whats the troubleshooting process for a 1/2 dead canbus?
Can't talk to most of the modules in the car for diagnostics.
Until I can fix the communication issues on the CANBUS
I won't be able to fix the SRS error.
So what I'm trying to figure out is how to fix it.
Whats the troubleshooting process for a 1/2 dead canbus?
Super Member
Joined: May 2009
Posts: 904
Likes: 22
From: Toronto, Ontario, Canada, eh!
2003 C230 Sports Coupe, Paprika Metallic Red, Auto, Pano, Leather
Todd,.... when I had issues with my ECU, my Mercedes Indy tested a number of things before making the call on the ECU, since ECU rarely go wrong. Anyways, when my Mercedes Indy tested my CAN-bus, he accessed it via all the wiring under the front part of the door sills an carpeting on the driver side. It's basically directly under the foot parking brake pedal,.... under that carpet where the carpet goes up to meet the door sills,.... there's a lot of wiring under there.
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Super Member
Joined: May 2009
Posts: 904
Likes: 22
From: Toronto, Ontario, Canada, eh!
2003 C230 Sports Coupe, Paprika Metallic Red, Auto, Pano, Leather
Todd,.... before you check your CAN-bus,.... double check all your fuse, relays and wiring,.... make sure wire to grounds are properly connected. Make sure there's no water in those corner compartment of the engine bay where the battery and front SAM are. Also, in your front SAM and rear SAM,... "rotate" your relays - with key out of ignition, rotate relay with other relay of same colour and size,.... relay basically come in either black, grey, yellow,... full size or half size,... it'll help to label the relays in a X-Y grid pattern,..
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MBWorld Fanatic!
Joined: Jul 2008
Posts: 1,005
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2013 UFO
I'm trying to clear my SRS error.
Can't talk to most of the modules in the car for diagnostics.
Until I can fix the communication issues on the CANBUS
I won't be able to fix the SRS error.
So what I'm trying to figure out is how to fix it.
Whats the troubleshooting process for a 1/2 dead canbus?
Can't talk to most of the modules in the car for diagnostics.
Until I can fix the communication issues on the CANBUS
I won't be able to fix the SRS error.
So what I'm trying to figure out is how to fix it.
Whats the troubleshooting process for a 1/2 dead canbus?
I have a spare one if that is of any use to you...
Super Moderator
Joined: Jun 2008
Posts: 19,942
Likes: 191
From: Llandudno, Cape Town, South Africa
late 2009 CLK 350 Coupe Elegance, '65 Jaguar S Type wires
List everything on the car that does not work. I'm not sure you have a CANbus issue. Only an issue talking to it.
I've given you the layout for the different CANbus's & the guide that gives you an idea how to look for shorts etc.
I've given you the layout for the different CANbus's & the guide that gives you an idea how to look for shorts etc.
Super Moderator
Joined: Dec 2006
Posts: 2,403
Likes: 64
From: Camas, WA
2007 C230SS; 2014 ML350 BT
Just like any CAN based network, divide and conquer. I am with Glyn, I doubt you have an issue with the CANBUS, just an issue with a module or connection. I would unplug all the modules that are giving you problems, then plug them in one by one. I bet you have a module that is overloading the CANBUS due to a connection issue or hardware failure of some-sort.
Newbie
Joined: Sep 2019
Posts: 5
Likes: 0
2007 Mercedes Benz S550
I technically have the same problem my 07 s550 which was actually finished in 05 wont start the dash and radio all work but no click nothing when turning the key it just turns and nothing I check the starter it works engine turns when shorting the wires but it also has a problem with the key being buggy and sometimes locking and unlocking the car sometimes not and the windows dont open except for the driver one then the tail or brake lights dont work then the display sometimes bugs out to and the radiator or ac fan run constantly when the car is off any help?
Newbie
Joined: Sep 2019
Posts: 5
Likes: 0
2007 Mercedes Benz S550
I technically have the same problem my 07 s550 which was actually finished in 05 wont start the dash and radio all work but no click nothing when turning the key it just turns and nothing I check the starter it works engine turns when shorting the wires but it also has a problem with the key being buggy and sometimes locking and unlocking the car sometimes not and the windows dont open except for the driver one then the tail or brake lights dont work then the display sometimes bugs out to and the radiator or ac fan run constantly when the car is off any help?
