Unable to read ABS/VDC on Subaru Legacy 2010 3.6L

[NickolayGerasimenko]

I'm trying to read ABS/VDC but failed with the following log:

Serial Pass-Through checkbox Prefer enabled

SSMP1communication::run():   operation: readRomId
SSMP1communication_procedures::setAddress(...):   sent read-request for address 0x8000
SSMP1communication_procedures::getID(...):   failed to read ID from control unit: timeout.
SSMP1communication::run():   communication operation error counter=0
SSMP1communication_procedures::setAddress(...):   sent read-request for address 0x8000
SSMP1communication_procedures::getID(...):   failed to read ID from control unit: timeout.
SSMP1communication::run():   communication operation error counter=1
SSMP1communication_procedures::setAddress(...):   sent read-request for address 0x8000
SSMP1communication_procedures::getID(...):   failed to read ID from control unit: timeout.
SSMP1communication::run():   communication operation error counter=2
SSMP1communication_procedures::stopCUtalking(...):   success.
SSMP1communication::run():   communication operation finished.

Is it possible to use SSMP2 Protocol? I tried to switch from SSMP1 to SSMP2, but it looks like SSMP2 supports only ECU and transmission.
Could somebody explain the differences in reading ABS/VDC vs ECU in a nutshell?

[Comer352L]

ABS/VDC controllers since ~2004-2006 are using another protocol, which isn't supported. I did some basic analyses, but never found the time to implement support for it.

[NickolayGerasimenko]

@Comer352L Thanks for the reply! Could you share more details on this maybe I can contribute to this?

[Comer352L]

The protocol is ISO-14230 (also known as KWP2000), but they are using lots of "vendor specific" functions.

[NickolayGerasimenko]

@Comer352L Thanks. Looking for spec now.
I have couple questions:

1. Does this protocol work through default serial driver? i.e can it work through serialCOM class? Or do I need custom driver be installed?
2. Do github implementations could help anyhow? like the following:
   https://github.com/aster94/Keyword-Protocol-2000/blob/master/src/KWP2000.cpp

[Comer352L]

Short answer: Implementing the protocol for serial pass-through interfaces is possible, but difficult and complex. Long answer: The protocol uses non-standard baudrates, an initialization sequence which requires some tricks, precise inter byte and inter message timings etc. A long time ago, there were several problems, such as Windows not being capable to perform sleeps which are accurate enogh for the timings and drivers not supporting non-standard baudrates. But to my knowledge, they have been resolved. serialCOM isn't a driver. It's a wrapper around the OS-specific APIs for the serial ports. J2534 interfaces usually support ISO-14230, so it would be much simpler to use them. The github project you mentioned seems to be designed for different interface hardware and lots of motorbike/engine specific services. So there's not much you can use from it. Anyway, because Subaru uses lots of vendor specific services specified for the ISO-14230 protocol, you would have to do a lot of reverse-engineering first.

[Comer352L]

I just noticed you have a 2010 3.6L. I'm not sure this ABS/VDC controller still uses ISO-14230. I'm pretty sure they switched to ISO-15765 CAN later, but I don't know when this change happened. Pin 7 of the OBD connector is used for the ISO-14230, so you should check your connector first. If the pin isn't there, it doesn't use the protocol for sure.