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G4+ Mazda RX8 CAN Bus


littlefeck

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  • 1 month later...

Just an update on this thread that I've learned about. The odometer doesn't count up distance covered. Apparently there’s a counter coming from the stock ECU to do the odometer, plus another message the ECU sends out to configure the ABS. The message differs depending on region though (UK, Aus, and USA are all different). 

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  • 3 months later...
  • 9 months later...

Here's an update on some info I've found from a guy who is doing an EV conversion.

he has done a lot of decoding to get his project working. 

His Youtube channel if full of useful info.

He's using Arduino but hopefully we can use his info with our ECU's.

here's some links to his stuff.

GitHub Page: https://github.com/DaveBlackH/MazdaRX8Arduino

Youtube explaination on RX8 BUS: 

 

 

Full Youtube channel: https://www.youtube.com/user/horndoggie999/videos

 

Cheers.

RX8CanBus20-05-2020.xlsx

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  • 11 months later...

The CAN setup is now close enough that the vast majority of stuff should be working.  It would suggest a wiring issue.  With the ign switch off, what is the resistance measured between CAN H & L?  Unplug the ABS and measure between CAN H/L there.  

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  • 6 months later...

Hey Adam,

I see AiM PDM32 has a odometer counter and can output custom vehicle CAN, do you think this would suffice to get the ODO function working on the factory dash or will this only work with the AiM dashes for the PDM32? 

While we're at it, I have been tossing up between a few PDMs recently, I've got it down to my top 3 so far. Moristech P30, Hardwire PDM25+ or the AiM Pdm32 They all seem to have similar costs. Would you have any recommendations Particularly in my street driven application?

Cheers.

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I dont know specifically what format the RX8 uses for the ODO signal.  I dont come across ODO in CAN streams very often but on the couple of cars I have it is just a counter that increments by 1 every say 10M, then when it gets to 255 it rolls back to 0 and starts again.  So you would need to know exactly what you have to recreate before you could conclude if any of these devices could do it.  

Of the 3 PDM's you mention, they are all pretty capable.  I suggest you play around with each software and try to set up some basic functions to get a feel for them.  I probably have example configs for all of them if you need something to play with. 

Moristech: Be aware it cant use a CAN keypad in standard configuration, it is an extra cost option if you want Keypad integration enabled.  The software has some quirks but it does work ok when you get used to it.  

The Hardwire one I havent had much to do with but I have helped set up a couple remotely.  Again a few quirks in the software that make it a bit frustrating to set up.  For example you have to drill down through about 3 different menus/windows to get to a basic common setting for some functions.

The Aim seems ok.  It was quite buggy when first released but seems to have been improved a lot since then and I havent heard many complaints recently.  Limited to Blink Keypads only, and if you have a keypad then 1 CAN bus is dedicated to the keypad and can do nothing else.   

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  • 1 year later...

The excel document halfway up this page suggests the ecu just reads the odometer tick from 0x4C0 and sends it out on 0x420, so possibly quite simple if that is correct.  Otherwise, since it is only 1 byte wide I would suspect it will just increment by 1 bit per fixed distance such as 0.1M, then rollover when it gets to 255.  G4X can calculate distance, G4+ cant.  

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On 11/24/2021 at 10:05 PM, Adamw said:

Try this, I have made a few changes to suit the G4X scaling and a few other fixes.

JaredsRX-8 V1.1.pclx 395.87 kB · 36 downloads

Here's what I see in the above file:

R/W Address (dec) Address (hex) Start pos Data
Read 1200 4B0 0 LF wheel
      16 RF wheel
      32 LR wheel
      48 RR wheel
Write 513 201 0 rpm
      32 wheel speed
  1056 420 0 ECT
      32 Oil light
      40 CE Light
      48 Charge light
  512 200 0 0
      8 0
      16 255
      24 255
      32 0
      40 50
      48 6
      56 129
  514 202 0 137
      8 137
      16 137
      24 25
      32 52
      40 31
      48 200
      56 255

Looking through this CAN setup, I have a couple of questions - based on the Blackhurst spreadsheet, the Chamber of Understanding blogs, and my own CAN sniffing, I don't see any messaging on (dec) addresses 512 and 514 (hex 200 and 202). Based on the linked config, streams 4 and 5 are written to those addresses, but I'm not sure what they're doing. Does anyone have more insight on that? My XtremeX comes in this weekend so I'll be able to test for myself soon.

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3 hours ago, Laminar said:

Looking through this CAN setup, I have a couple of questions - based on the Blackhurst spreadsheet, the Chamber of Understanding blogs, and my own CAN sniffing, I don't see any messaging on (dec) addresses 512 and 514 (hex 200 and 202). Based on the linked config, streams 4 and 5 are written to those addresses, but I'm not sure what they're doing. Does anyone have more insight on that? My XtremeX comes in this weekend so I'll be able to test for myself soon.

Bottom of my post here shows those.  It came from one of the EV forums, some models require these dummy messages to start up the steering pump.  The rally car I done came to me without an OEM ecu so I couldn't sniff anything myself, but it did need these.  

 

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