Smart Roadster CAN Bus Connector/Port

The CAN bus can be accessed behind the tachometer on the Micro-CAN connector (18-pin) of the system plug (the wires must not be disconnected).

High signal is on pin 14 (red/brown).
Can low is pin 17 (black/white).

ATTENTION.

The color coding appears twice on this cable strand, and the correct two wires are twisted together.

CAN bus speed is 500 kbit/s.

Behind the CD slot (or ashtray, or on-board computer) in the center console is a thick bundle of cables. There should be a 9-pin connector or distribution block located there.

3 black and white Can-Low prints.
3 times red/brown, Can High.
(and 3 yellow lights for mirror adjustment, if available).

Sebastian.

'Only the powertrain CAN bus is present. The CAN bus is connected through the SAM module and the instrument cluster. All other control units are connected in a parallel configuration (e.g., ESP, electric power steering, steering angle sensor, engine control unit, etc.).'

Hello Sebastian,

Have you already found the 9-pin Amphenol connector behind the console? I haven't checked yet.
I'm still not quite understanding your PS - but it's also early days . The other control units are wired in parallel with the SAM and combination instrument, which is good, but what does that mean? Can you not access the entire CAN bus from that connector, or only the SAM and MEG? Does the Micro Quadlock that 'The Lebowski' describes offer the same bus, or a different one? Could you please explain this? I'm trying to get an idea of which car PC architecture might offer an elegant solution, even though this topic might be a bit premature. We should first explore how we can deal with the CAN bus.

Best regards, Guido.

Hello Guide.

I believe you should be able to access the full CAN bus everywhere. I don't have precise information about that. It seems like the bus is simply passed through the instrument cluster. It's not explicitly shown in the wiring diagrams for the SAM module, but I don't think it has any filtering functions. I need to check again which control units are located on which side.
I think the bus system is integrated in a way that you can't operate the vehicle without these components, while other control units can simply be disconnected and the rest should continue to function.

I believe the control unit for electric power steering is the easiest to locate. It's located in the passenger footwell, on the center tunnel. However, I haven't checked it myself yet. Once I have the adapter, you'll be able to see photos of it on the Smart-Roadster forum. (I estimate it will be available in about 10 days, as I'm away for a week starting tomorrow).

Sebastian.

The initial attempts have been made, and so far, it doesn't look too bad.
ID | DLC Data | Period Count | Comment
055 8 00 99 2B 27 00 00 00 00 19318 7
080 8 00 00 00 00 00 00 00 00 19 34044
090 8 04 81 7E 7F 00 2C 00 00 19 34042
0C2 8 22 00 00 00 01 50 00 8D 9 68098
110 8 FF 00 00 00 00 00 00 19 13
190 8 4C 08 28 01 A2 5D 00 00 19 34964
199 0 RTR 0 1
208 8 18 21 FE 00 00 80 82 00 19 34042
210 8 51 01 FF 24 40 00 00 00 19 34966
220 8 81 04 00 95 11 01 00 00 19 35026
238 8 00 11 00 00 00 00 00 00 19 35036
23A 6 00 00 82 00 00 00 24 27231
300 8 00 03 F6 11 40 04 00 00 19 34967
310 8 0B 09 39 09 00 00 4D 7E 9 69930
330 2 40 00 503 1329
510 1 7F 24 30
515 7 41 09 00 95 00 11 2C 493 1362
560 8 03 00 00 00 00 95 00 7C 39 12
631 8 FE 04 04 04 04 04 04 04 9 69933
t22 0 RTR 0 1

I guess that...
ID 310: Drive.
Throttle position (0-250).
Byte5 ditto? (0-46)
Byte 7: h40 Brake pedal.
h20 idle state; h08: automatic mode; h10: reverse gear (only one bit is set in each case).
Byte 3: Speed?

ID 0c2: Steering.
Bytes 1 & 2: Steering wheel position.


I hope this is discussed extensively on the Smart Roadster forum and that a few more people will join in to help.
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Sebastian.

Hey everyone, I also wanted to introduce myself on this forum. 'vespadriver' is really doing great in the Smart forum and has already achieved quite a bit if he continues like that...

But maybe some of the people who read this will be interested in taking a look and sharing their experiences with us, especially regarding how they value information and find it.

Since a Vespa driver can sometimes feel quite alone out there, it's definitely a specialized topic.


Best regards, Sebastian.

It's been a while, but are there any new developments regarding CAN IDs for the Smart car? I might be able to contribute information about climate control and lighting functions, if that's still of interest. I was able to decode that part of the CAN bus.

Best regards, Stephen.

I also found something else:

ID 0x210

Byte [0] = Intercooler temperature * 0.5
Byte [1] = Boost pressure (Engine OFF = FE; Engine idling = 00).
I'm not sure whether it's related to the EGR valve or the boost pressure. I have no idea what the minimum and maximum values of the sensor are.

ID 0x515

Byte [6!!! not 7] = Tank capacity * 0.5

Is the CAN bus connected to the CAN pins on the OBD connector?

Has anyone ever tested this before?

chipy wrote:

Is the CAN bus connected to the CAN pins on the OBD connector? Has anyone ever tested this before?

With a properly functioning OBD2/OBDII system, yes!

What is correct?

To the best of my knowledge, the OBD port is legally required.

If the CAN pins are not connected, does that mean they are not properly configured, and is that permissible?

chipy wrote:

What does "richtig" mean? To the best of my knowledge, the OBD port is legally required. If "not correct" means that the CAN pins are not connected, is that permissible?

Source: Wikipedia.

In Europe, it is mandatory that... This applies to cars with gasoline engines from the model year 2001 and to cars with diesel engines from the model year 2004. However, vehicle models intended for export to the USA often have OBD(-2) compatibility even in much older production years.

So, everything that came before in terms of OBD wasn't always "standardized." Germany lagged behind when it came to OBD. The Americans were quite quick with it.

OBD has been standardized since the years mentioned above. Therefore, manufacturers could do whatever they wanted back then, including not connecting CAN to the connector. Additionally, in my Smart and likely in other models, the KWP2000 protocol is used with K-Line and L-Line connections.

Was wäre, wenn dies überprüft wurde, um festzustellen, dass der Smart OBD keinen CAN-Bus hat, oder woher stammt diese Information?

This was discussed in a relevant forum, which I am also a member of.

The OBD connector in older models (pre-2001 for gasoline engines, pre-2004 for diesel engines) uses the K-line protocol within the KWP2000 standard, or other protocols.

And you have a diesel engine from 2003, which is before 2004?

If your car has a CAN bus, I would personally check to see if it's present on the OBD pins; there's no reason why it shouldn't be.

The fact that other protocols and pins might be involved doesn't rule it out; perhaps they couldn't read the CAN bus back then, which is why these old protocols are also necessary.

chipy wrote:

And you have a 2003 diesel and that's before 2004? If your car has a CAN bus, I would personally check if it's present on the OBD pins; there's no reason why it shouldn't be. The fact that other protocols and pins exist doesn't exclude this possibility; perhaps they couldn't read the CAN bus at the time during the initial vehicle inspection (ASU), which is why these must be older protocols.

Check the Raspberry Pi thread; I posted a diagram of the pin layout there. There's no CAN bus! The pins that are present there are the K-line and L-line used in the KWP2000 protocol, but not on gasoline models. Since my Smart is from before 2004, this further confirms that there is no OBD2 system, which uses CAN.

As I mentioned, there might be models from other manufacturers that already had OBD2 before the legally required production years. Before the standard was implemented, manufacturers were free to connect whatever they wanted to the "OBD" connector. For example, GM standardized OBD2 much earlier, but this was proactive and exemplary; however, they weren't obligated to do so for the German market. For diesel vehicles, the vehicle inspection (ASU) has been performed using the OBD connector since the production year 2004. And for gasoline vehicles, it's been done since 2001! That's when these "readiness codes" come into play.