OEM CAN dash setup

[jonnyt80]

Im trying to see if i can get the CAN operated dash to work via the G4+ Xtreme. Now im using CAN2 and wired as per diagrams i have been able to get hold of. I do have some CAN data i found online so how do i go about setting this up?

I have used user defined drop down but unsure how to proceed and test

I have added a screenshot of the data i have found. Its on a ford mondeo ST220

[Scott]

Good work on finding the data online. One other thing you will need to find out is what bit rate the CAN bus communicates at, most vehicles are 500 kbit/s.

One other things you're going to need to do is convert the hex CAN IDs you've found into decimal number, as this is what the Xtreme uses. Windows calculator can do this easily when set to 'Programmer' mode.

Here is how I think you would set up Engine RPM:

Remember to do a  Store to the ECU after clicking Apply and OK.

Scott

[Adamw]

Scott, I haven't yet needed to learn much about CAN so for my own learning I'm curious about the above example...

I see that in the message ID201 there is RPM, speed & fuel level? (and probably other stuff we cant see). Would it be normal for all the data in one message ID to come from one device (lets say the engine ECU) or can a message be generated by multiple devices all adding data to the same message ID (for instance eng ecu and BCM all add data to that same ID).   It seems strange to have fuel level on the same message as RPM?  I should probably google it but since you're on a roll...

  

[Scott]

Hi Adam,

Yes, I would expect (based on the info provided) that all these parameters (RPM, SPEED, GAS) would be in the same message. Each controller on the CAN bus transmits certain CAN IDs, and no two controllers send the same CAN ID. The message is broadcast, so all controllers receive all messages. However the controllers are programmed to only pay attention to CAN IDs that apply to them. It is common to find multiple related data being transmitted on the same CAN ID. For example, a CAN ID from the ABS controller might contain all for wheel speeds, each wheel speed taking two bytes of the messages 8 bytes.

Each byte has 256 possible values, and for a lot of parameters (like engine speed) this is not enough, so two bytes are used. This gives up to 65,536 values, which is much better. More simple data can use one byte, or even less.

Scott

It seems strange to have fuel level on the same message as RPM?

Maybe it is not fuel level, but fuel usage that is being sent from the ECU to somewhere like the dash. This can be used for a fuel computer.

Scott

[Adamw]

Thanks, that pretty much confirmed my basic understanding.  It was my assumption that GASH & GASL was a fuel level measurement that was not making sense to me so your suggestion that it might be fuel consumption would fit better. 

[jonnyt80]

Thanks scott. I have tried setting up as you have suggested but no luck as of yet. I will play around with it when i have time next week. 

Is there anyway other than a sniffer to test the CAN output from the ecu?

[Scott]

The byte order can go two ways, Most Significant First or Least Significant First. Most Significant is more common, and what I did on the 'streams' tab above. Here is how you would set it up for Least Significant:

Give that a try also.

You can test that CAN 1 is working, by bridging it to CAN 2 (H to H, L to L), and then configuring CAN 2 to receive the data as something (CAN Volt channel maybe?). Then monitor the CAN Volt channel and see if it is displaying data.

The other option is a CAN sniffer, which is a handy tool.

Scott.