SSM for OBD1 and OBD2 SVXs

[Huskymaniac]

There were bit of this on two different threads and I have an update so I figured I would just start a dedicated thread to make this easier for people to find later.

As mentioned previously, I bought two cables from the evoscan folks. One cable is a two-headed usb to both OBD1 and OBD2. This cable is meant to communicate only over the SSM pins using the SSM1 protocol. What we verified was that the OBD2 cars built from 1996-1998 use the SSM1 protocol, not SSM2. However, the memory addresses for the parameters were all different. I also bought an usb to OBD2 cable for my Tribeca which is supposed to be able to communicate over either the SSM pins or the OBD2 pins. I have not tested if it can use either SSM1 or SSM2 protocol or just SSM2 protocol over those SSM pins.

Thanks to information provided by Phil I have been able to determine most, if not all, of the memory addresses for communicating with OBD2 SVXs using SSM1. I have both the ECU and TCU addresses now and will eventually work on the climate control unit too.

On software, I have only played with my SVX so I can't say anything about how well any of them work on either newer OBD2, non-SVX, cars or OBD1, including SVX, cars. However, many people have played around with these packages for these cars and I assume the work fairly well. The gray area was with OBD2 cars from 1996-1998, including and especially SVXs.

The evoscan software is really nice BUT it can't communicate with the TCU or any other unit besides the ECU. What is can do is communicate using SSM1, SSM2 and OBD2. It has a variety of memory definitions for OBD1 and OBD2 cars and I have updated that file with the definitions for OBD2 SVXs.

JECScan is pretty bare bones and appears to be meant for communicating only with SSM1 protocol. BUT, it CAN communicate with the TCU and, hopefully, the climate control as well as other controllers. It looks like this software might be able to also communicate using SSM2 but I haven't tried it.

The released version of FreeSSM can only communicate using SSM2 so it only covers Subarus built after 1998. HOWEVER, I am working with the author to obtain a development version of the software that can communicate using SSM1. This is a major undertaking for me as I am not up on the new compilers and development servers. It may take some time to get a version of this working on OBD2 SVXs but the software appears to be better than JECScan and has the ability to talk to the TCU and possibly other controllers as well.

As far as the definitions for the memory addresses of the various parameters, here is what I believe is currently working for OBD2 SVXs:

ECU: Battery voltage, speed, RPMs, coolant temperature, ignition advance, MAF, TPS, engine load, injector pulse width left and right, idle control valve duty cycle, all three O2 sensor readings (average, max and min), air/fuel correction left and right, knock correction, atmospheric pressure and manifold relative pressure. I think I also have all three O2 heater signals too but I'm not entirely sure.

TCU: Battery voltage, both speed sensors, RPMs, ATF temperature, TPS, current gear, line pressure solenoid duty, torque converter lockup solenoid duty, center diff solenoid duty, MAF, TPS source voltage and two digital IO bytes that I haven't completely figured out yet.

I have the definition files for both the evoscan and JECScan software if anyone wants them. I hope to eventually have the definition files for FreeSSM too. And one other note about software is that these programs have other capabilities besides just reading ecu and/or tcu data. The evoscan program, with the appropriate cable, can flash some of the newer ECUs. It looks like JECScan can get a ROM dump. But all I really wanted was an SSM reader for my OBD2 car and it appears as though I am well on my way to that goal. And all you really need is a $57 cable and, maybe, a $20 software package and you can get an SSM reader for any SVX.

[pearlm30]

Thanks a lot for the update!

[jellybytes2]

Great info.. thank you.

[processengr]

Thanks Tony! Great news! I am ordering the cable this weekend.
I also have an "Ultraguage" to to test, will let you know what it reports when I plug it in to the 97. I already know that it cant read any TCU data.

[Huskymaniac]

Originally Posted by processengr

Thanks Tony! Great news! I am ordering the cable this weekend.
I also have an "Ultraguage" to to test, will let you know what it reports when I plug it in to the 97. I already know that it cant read any TCU data.

As I shake down the various software options, I am constantly revising the definitions files. Let me know when you get the cable and what software you want to try and I will send you what I have. Hopefully, by then, I will also have something for FreeSSM. I need to build what would effectively be the first TCU definition file for that software.

[Huskymaniac]

On a side note, has anyone been able to download and install the software from ECUTune? I extracted the files and tried to run the "click once" file but it said it was missing files.