Hondata

Hi,
Im trying to set up CAN output from my s300 to a RaceCapture Pro Mk3. Everything appears to be setup correctly but I’m not receiving a signal on the RaceCapture.

Following wiring diagrams for the devices CanH and CanL are properly connected. A 120 ohm resistor was wired between H/L near the ecu and termination enabled within the RaceCapture. I’ve matched baud rates in smanage and the RaceCapture and tried both CAN channels available on the RaceCapture.

I’ve tested continuity to confirm pinout to s300 pins and 120ohm between h/l.

I’ve confirmed smanage shows CAN output set to Hondata format at 500kbps, I’ve also tried the Motec format. No signal is received in either calibration. I’m monitoring with a sniffing function on the RaceCapture, which I’ve confirmed reads traffic when connected to my OEM Acura TSX ecu. (S300 is in my Integra).

Testing voltage on the CanH and Can L pins on the s300 Can H is only reading 2.3v, and reads this even when I set CAN to disabled. Can L reads ~2.2v again seemingly regardless of CAN configuration. Is this expected? Continuity between the pins Is 80k ohm (connector removed from pins) or above which corresponds to standards I believe

Is there anything else I can try to test to validate if the CAN output from the s300 is working properly? Or generally anything I’ve missed on the setup that could interfere?

Thanks,

Alan

Use a multimeter to confirm that both CANH and CANL have about 2.5v when disconnected from the rest of the bus. ie test the voltage on the s300 end and then the RaceCapture with them both disconnected.
After that you need to start using protocol analyzers or oscilloscopes to check the waveforms. These are not expensive, but a bit involved.
Usually I find it is a missing termination resistor, the CANH and CANL being switched, the wrong bit rate or the wrong CAN description on the receiving end.

So yeah, I must have been stuck on stupid and had CAN (1&2) swapped so kept sniffing the non active network. Working now with a few weird behaviors.

TPS specifically seems to come in @65000+ until a little pressure on the pedal then registers (still need to compare if there’s any off set) thinking this could be signed and not scaled as set in parameters since I think I read -.12% throttle closed. If so this might complicate things as the tps sensor I have the s300 reads 105% full open without scaling :s

Confirmed CAN documentation doesn’t seem to show it but TPS value is signed. It also seems to be the unscaled value, which in my case is about -.12% leading to the initial odd value.

I’m confused by the lambda value. Documentation shows conversion formula 32768/ lambda (lambda) which I read as 32768 divided by the transmitted value to get lambda. I was struggling to reorder this since mapping is only in (transmitted value)*x /y +z format. In the end I just plugged in (transmitted value) /32768 and I seem to be getting a correct lambda value? Is the documentation flipped or am I misreading it somehow? This seems like it would be a highly consumed value so I feel like I’m somehow misreading.