×

Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Course Question - Requesting CAN Data From ECU

CANBus Communications Decoded

Forum Posts

Courses

Blog

Tech Articles

Discussion and questions related to the course CAN Bus Communications Decoded

= Resolved threads

Author
312 Views

I've got an OEM Nissan ECU (2011 USDM VQ37VHR) which I believe uses their Consult-III protocol on the CAN bus. There are a few things which are broadcast (like the coolant temperature) which are easily sniffed and interpreted ... however there are many things which I'd like to get at which must be requested from the ECU.

Does the course cover parameters which must be requested as opposed to dealing with what is simply broadcast ? I'm looking to get the MIL / check engine light status amongst other things.

EDIT: I should add this is in an engine swap context where I have the engine ECU only, not the BCM / IPDM etc which potentially would poll for check light status in an OEM setup.

David,

It covers sniffing CAN and messages on the bus in general. Most of that process involves observing a behavior and then being able to repeat it or interpret it.

MIL status is part of the OBD2 standard and has to be easily accessible so a standard OBD2 request can be used.

Reverse engineering a dealer scan tool is not covered by the course specifically, but most likely that will not be required to get the info you're hoping for.

almost everything you should want will be on the obd2 port, the only things not on the obd2 port will be mostly found under the sae j1979 pids.

VVEL information is on a 2nd bus under the hood if so equipped and can Alternatively be found with mode 22 PID requests if you cab request access with a specific message.

most motorsports systems aren't designed to do higher level, multi message, dynamic communication, so it becomes a inherent struggle without building/ developing a device to do such

A good source of information on OBD2 CAN protocols (what PIDs are available, how the requests and responses are formatted, etc) can be found on Wikipedia.

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

Thank you for the comments folks, appreciate it :)

I've ordered a proper CAN to USB adapter which I will need to dig a little deeper into what I am seeing and validate what I am sending via my Arduino code is what I really need to get on the wire etc. I've captured some data from both UpRev and an ELM bluetooth adapter but can't reliably reproduce this as yet ... there is potentially a 'diagnostic mode' the ECU needs to be in also to query via 0x7DF messages also.

Will report back when I'm able to debug things better. My Arduino code / project is here if anybody wants to take a look: https://github.com/david-morton/BMW_E46_Gauge_Cluster_Control

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?