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  #76  
Old 05-28-2007, 05:08 PM
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Quote:
Originally Posted by Trevor
On the basis of this, it would seem illogical to propose that there is a difference between the JDM and Euro systems, when the only requirement is the provision of a manual switch, for power mode in the JDM system. This surely would not involve extensive circuit or software changes.
Hi Trevor!

We know that the Euro and JDM TCUs are not the identical because various people have tried to fit JDM boxes to his Euro cars and vice-versa. There are various problems with regard to speed sensor #2. Plus, of course, the the Euro car goes into "economy mode" on the same signal that the JDM car uses for "power mode".

I think it is just a small difference in the software. If I can get a download of a UK TCU then I'll compare the two and we'll know for sure.

Regards, Phil.
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Last edited by b3lha; 05-28-2007 at 05:12 PM.
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  #77  
Old 05-28-2007, 05:31 PM
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I promised pics of my test setup, so here you go!

First, my proof. Note the speed and revs; I was parked!



And a picture of the temporary setup. I've since pulled the wire and am thinking about a design for a more permanent setup.



And a picture of how I got it into the TCU... (ignore the Alpine iPod unit, haha)



And wiring it into a ground. Heh. Gotta love those diagnostic wires being so close by!



Enjoy.
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  #78  
Old 05-28-2007, 05:39 PM
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That's awesome Nomake Wan. Great photos. You should copy those posts into a new thread where people will see it. It's going to get buried in pages of geek talk here.
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  #79  
Old 05-28-2007, 05:45 PM
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Quote:
Originally Posted by b3lha
Hi Trevor!

We know that the Euro and JDM TCUs are not the identical because various people have tried to fit JDM boxes to his Euro cars and vice-versa. There are various problems with regard to speed sensor #2. Plus, of course, the the Euro car goes into "economy mode" on the same signal that the JDM car uses for "power mode".

I think it is just a small difference in the software. If I can get a download of a UK TCU then I'll compare the two and we'll know for sure.

Regards, Phil.
My guess is that the inputs are the same and the difference is how they are applied. This would mean similar hardware, but different software, which is your baby.
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  #80  
Old 05-28-2007, 05:50 PM
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Quote:
Originally Posted by Trevor
Joe,


As a result of this arrangement, the same TCU could be used for both systems. This would appear logical and confirmed by the different solenoid configurations, as is used to operate clutch, or alternatively centre differential as are involved.

On the basis of this, it would seem illogical to propose that there is a difference between the JDM and Euro systems, when the only requirement is the provision of a manual switch, for power mode in the JDM system. This surely would not involve extensive circuit or software changes.
Hi Trevor

Your logic is good, and we have already gone down this path of assuming they should be the same, or did not need to be different. In practice they are different, and some of this difference is down to the use of a different speed sensor yielding a different pulsed signal. The control circuitry has to interpret these pulses [from the two different types] and Phil has postulated [correctly as I see it]that some of the mapping in the different TCUs takes account of the different final drives the markets come equipped with to determine road speed.

In my own case, I took it a step further and fitted a JDM TCU to my UK car. It did not work properly, the odometer was flying forwards at an impossible rate, about aircraft speed.

Another clue to the differences would be Pin 4. When earthed in the UK type, it turns on Econ mode, rather than Power. Econ is the diametric opposite of power. When switched on, it denies access to the power map, and maintains the car driving in Normal all the time. As the input pins are different, so the internal circuitry must be different. Not a lot, I'm sure, just different.

It does appear that now that Nomake Wan has grounded the Pin 4 in the US type and switched on Power, that this confirms the US software is at least similar in that respect to the JDM software. For those same model years.

It wouldn't surprise me if the later years that don't light up the power light are different again, because of OBD 11 circuitry.

Great progress, I'm thinking!!

Joe
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  #81  
Old 05-28-2007, 05:58 PM
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Quote:
Originally Posted by Nomake Wan
FORGET ALL THAT!

I just ran an experiment on my car... and it was a SUCCESS!!!

I'll provide pics at the end, but for now I'll just explain what I did. I pulled the harness out of the bottom of the TCU, sure enough position 4 was missing a wire. So I took a piece of wire from my tranny resistor project, coiled it up, and put it in through the back of the harness, then put the harness back into the computer. As for ground, I rememebred that the ECU goes into diagnostic mode when you ground pin 2 on the harness... and to do that you put the end of that blue wire in it.

So I coiled up one of the blue wires with the end of my wire. Starting the car saw no change, backing out of the driveway was no different... but damn. I put it in Drive and the POWER light came on and just... it just WENT. Holy crap. I did a test drive around the block and it was just so solid. Having POWER mode on like that is just such a cool feeling.

So I have confirmed that grounding pin A4 on the TCU does in fact grant you unlimited POWER mode whether you have a JDM car or a USDM one. Can't comment on the UK ones, but my thought is this: if they just didn't put in the switch in the USDM TCU, then why would the TCU in the EDM models be different? It's so much easier to just reverse the switch function! If the "POWER" switch on JDM models grounds A4, then why can't the "ON" position for the Economy switch just be an open circuit for pin A4, and the "OFF" position be ground?

Dunno. Anyway, it felt awesome, that was a very cool experiment. I'll have to rig up something more permanent real soon.
This is totally cool, Nomake. You are now LEGEND!!

As Phil suggests, we need to write up a full How-To on this. Using the blue wire is OK on a temporary basis, but the correct way is to install a console switch, just like the JDM models have. Run your wire to it from Pin 4, and you can switch in and out power mode as you wish!!.

And as Phil mentioned, same as I used to do, you will leave it on full time, the drive is better with it ON.

Joe
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  #82  
Old 05-28-2007, 06:04 PM
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Joe, none of what I put forward is in any way contra to what you are now saying. What I was saying is that the guts of the animal is probably similar from a production stance. Connecting do dads, and inputs may be different, but it would appear that the internal TCU hardware could be basically the same. Phil is the man to provide answers beyond the speculative.
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  #83  
Old 05-28-2007, 06:14 PM
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Quote:
Originally Posted by svxistentialist
This is totally cool, Nomake. You are now LEGEND!!

As Phil suggests, we need to write up a full How-To on this. Using the blue wire is OK on a temporary basis, but the correct way is to install a console switch, just like the JDM models have. Run your wire to it from Pin 4, and you can switch in and out power mode as you wish!!.

And as Phil mentioned, same as I used to do, you will leave it on full time, the drive is better with it ON.

Joe
Nomake has confirmed what I have always suggested, i.e. that the inputs are simply used in different ways, in order to achieve a desired result as has been called for, or dictated, by the sales dept.
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  #84  
Old 05-29-2007, 12:17 AM
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Quote:
Originally Posted by Trevor
Nomake has confirmed what I have always suggested, i.e. that the inputs are simply used in different ways, in order to achieve a desired result as has been called for, or dictated, by the sales dept.
I do see what you are saying Trevor, or at least I think I do. Pin 4 grounding provides Power for one market, or provides Economy for another market, as dictated by the sales or marketing people.

However, the fact that the same action, grounding that pin, in two different [but broadly similar] boxes causes the TCU to behave in different ways does indicate that the circuitry behind the pin and the software responding to the inputs that the circuitry feeds is different.

Phil is checking the functionality at code level. If every wire feeding the three connectors was the same colour in both markets, and coming from the same blocks and the same output sensor circuits, you could postulate that both TCU types were the same. But even in that circumstance, if the feed to ONE pin [such as our a4 B66] caused a different output or functionality, you would have to presume that the firmware/software on the internal board in each TCU was unique or different for each market.

So the internal TCU hardware may be the same as you say, but the software must be different.

Joe
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Last edited by svxistentialist; 05-29-2007 at 12:19 AM.
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  #85  
Old 05-29-2007, 01:36 AM
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When you ground pin a4, bit 6 of memory location 0011 in the TCU changes from 0 to 1.
That's is all. Whatever happens next is governed by how the software interprets that input.
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  #86  
Old 05-30-2007, 07:23 AM
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I was surprised to se this much of a response!!!!!!!!!!

It is really nice to see so many people proficient in this subject!!!

I am totally lost with all of this.

Maybe a few of you could help me out with a few questions I have?????

I am thinking of wiring up the ScanGauge2 to the select monitor adapter. This seems straight forward enough.

If I plug this in...... will it kill anything in my SVX? Well if it's wired correctly that is.......

The ScanGauge2 does have the capability for user input of hex codes and to get back responses. It lets you look at four digital values for guages at one time and would fit on the instrument panel. It does have some advantages.

I am really after the AT temp hex code and a few other items. Seems I might be able to find this for my 92 if read thru all the information this thread links up to !!!!!!!!!
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  #87  
Old 05-30-2007, 07:36 AM
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As long as you wire it correctly, you're not going to damage your car.

But at the moment I don't think the software is up to doing AT temp yet... you can look for the hex codes yourself I guess but... yeah...

G'luck man, don't fry anything.
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  #88  
Old 05-30-2007, 10:33 AM
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Does the scan gauge work on your SVX? I had a look at the website and it says it's for OBD2 vehicles. But your profile says you have a 92 SVX, which would be OBD1.

OBD2 is completely different to OBD1. But if you have an OBD2 SVX then it should work just fine.
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Last edited by b3lha; 05-30-2007 at 10:36 AM.
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  #89  
Old 05-31-2007, 08:05 AM
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I have not tried the ScanGauge2 on my SVX at this time. I am thinking about giving it a go though.

I am wanting to know about making up a cable to go between the yellow monitor connection and the scangauge. I think I can use the pin connections you have given us and get the other side from scan gauge people.

I just want to be sure I will not break the SVX or the scangauge2

I have learned something interesting about the scangauge2
In the ScanGauge2 manual (available on their site) there is a problem listed for the OBDII 95 to 98 Subaru's. ScanGauge had to write special software to get the Subaru's to work!!!! I talked to a person about this. He said that Subaru was not in compliance with OBDII for these years!!!!!! So I was thinking maybe the 92 SVX would be the same. Well I am not sure now since your 92 is different. But maybe the 92 USA version.....

Any thought you are willing to give me on this will be accepted with graditude.

I think the work you are doing is great and I would like to join in but I do not have enough time currently. I also get completley lost trying to follow the thread. I have always thought it would be great to record data as function of time for my commute and plot it back out, datalogger. I think from what i have read your software can do this. I think then I could find the most efficient MPG for the SVX!!!!!!! I drive a lot..........

Thanks.
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  #90  
Old 05-31-2007, 08:48 AM
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For the SVX, the only years that are OBDII are 96 and 97. 92-95 are OBDI so chances are your OBDII software isn't going to be able to make heads or tails from the output of your 1992 SVX computer.

However, as long as you create the connector properly (no grounds where there shouldn't be), you do not risk damaging either side (SVX or computer) by trying. Whether you'll get useful data or not, though, well... experiment, I guess?

Just realize that 1992 through 1995 do NOT use OBDII at all. And that therefore, chances are the ScanGauge is NOT going to work on these cars.
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