no vehicle speed

[FoxSTI]

Hello everyone,

I purchased my first motec product - C125.
I am very quickly learning the ropes of configuring it but I need some help.

I have bought the ODB2 cable as I do not have a motor ECU. My car is a 2015 Subaru STI.
I am only able to get GPS Speed, but it doesn't matter what I do (adding the proper channel to the dash) I can't get the Vehicle speed channel to give me the car's speed.

I would like to get that working as I want to calculate my gear based on that and not GPS.
I have tried other devices via ODB2 and I am able to get a speed reading.

Could my ODB2 cable be damaged - I am out of ideas.

Thank you

[David Ferguson]

Are you receiving any channels from the ODB template? Perhaps the issue is the wrong CAN baud rate (typical production automotive are 500k or even 250k).

Where are you located and have you asked the MoTeC dealer that sold you the dash for help?

[FoxSTI]

David, I believer I am. For instance I can see engine temp and rpm.
I am located in south fla. I bough my C125 from Milspecwiring.com I was refereed to them by Motec East.

I just took a quick look under "Communications setup" and under CAN 2 I see Vehicle Speed.
the Mode is set to CAN and rate 500K

[David Ferguson]

Well, Milspecwiring.com is a website operated by the MoTeC East folks

I think the problem is that the ODBII_TX template doesn't request the vehicle speed by default. There is a MoTeC tech note on the ODBII support (ask MoTeC East for that, I couldn't find it to download). It details how the ODBII_TX template sends requests for specific ODBII PIDs, and the ODB Service 01 Reply Comp template receives the responses. Not everything that the receive template is configured for is requested by the ODBII_TX template, because not all vehicles will respond to every request. Vehicle Speed would be an 010D request.

If you want to learn more about ODB-II PIDs, the wikipedia page is a pretty good resource:

https://en.wikipedia.org/wiki/OBD-II_PIDs

You should be able to get this working with their help.

[FoxSTI]

thanks for your reply David. The wikipedia you cites makes sense.
The OBDII_Tx table is empty (Transmitted Channels).

The CAN 1 tab is also empty.
What is the difference between CAN 1 and CAN 2?

It is funny for lack of better tern that RPM and Throttle position and other signals work but Vehicle speed does not.

Here is what I see when I go deeper into the dialog boxes.
I see and id of 410D. Not sure what the ID Mask is nor the offset. is 410D the same as 010D?



I reached out to Motec East today vie e-mail, I am starting to loose hope.

[David Ferguson]

I'm sorry you aren't getting the support you need. I would think dasupport@moteceast.com would be pretty responsive.

To answer your questions:
What is the difference between CAN 1 and CAN 2?
Your C125 has two separate CAN bus connections available. Often the Vehicle CAN bus will be on one connection (ie. CAN2 for your ODBII connection at 500k baud), and the other CAN bus might be used for MoTeC products operating at 1Mbit, like an SLM, or Video Capture System.

I see and id of 410D. Not sure what the ID Mask is nor the offset. is 410D the same as 010D?
That is in the receive template -- in the Response section of the Wikipedia page it describes the messages returned, and 41 + PID indicates the current value of the requested PID. So the important thing is the "OD" means Vehicle Speed, 0C is Engine Speed, and 11 is Throttle Position


Anyway -- here's what you need to do. I don't have the ODB tech note in front of me, so this is from memory as to how the transmit template works

-- Select the ODBII_TX template in the Communications Setup window.
-- Click the Edit... button, then the Transmitted Channels tab.
-- This is a list of ODBII requests that are sent out on the bus. It only sends one message each 20 milliseconds (ie, 50 hz total). In sends the messages in a way that causes the ones on the top of the list (1-8) to be sent more frequently than the ones on the bottom of the list (9-16). You will notice that some on the top of the list are repeated causing them to be updated even more frequently like RPM (010C) and Throttle Position (0111)
-- Select an empty identifier row, and click the "Change ..." button and enter Offset: 1, Identifier: 010D, and Identifier Mask: FFFF (Heck you could change the 010B rows if you would rather have vehicle speed in place of Intake Manifold Pressure -- notice that is a repeating one that will be updated frequently).
-- Click OK to close the Compound Message Identifier window.
-- [Optional] I would then click the Save As... button and save my template with a new name (I have an ODBII_Nissan_TX that I modified). After you click the OK button to dismiss the CAN Communication Setup window, you will notice that your template name was changed.
-- Exit the Communications Setup window with an OK, and transmit your configuration to the dash. If your vehicle supports the 01 / 0D PID for Vehicle Speed, then that channel should be updated.

Hope that helps.

David Ferguson
Veracity Racing Data
Paso Robles, CA
805.238.1699

[FoxSTI]

wow this is really staring to make sense !!!!
you are right, 010D is nowhere on that list.

What is "Offset" and "ID Mask" ?

So if I want t Oil Temp (provided my car does have sensor) I can add 015C - or any other channel for that matter?

- So silly the did not add VEHICLE SPEED to the out of the box template. I am going to flash the dash in the morning and see if this works.

[David Ferguson]

There are several MoTeC webinars on CAN that explains all the terms. Check out:

http://www.motec.com.au/webinars/webinararchive/#CAN

Yes you can add different PIDs, or change the order so that some update more frequenty. Something like a temperature channel would be placed at the bottom of the list as they typically update very slowly.

[FoxSTI]

David,

Is it safe to say that I can only request 16 channels from the car via the ODB2 CAN?
8 with more frequency than others?

[David Ferguson]

Yes, that is my understanding.

Now, perhaps there is more CAN data being transmitted than ODB polling. This is where you get out the CAN bus analyzer and start to reverse engineer the OEM CAN bus. I would also ask motec east if they have any CAN template for Subaru's, you never know there might be something like that already done.