eulogious

What, you haven't driven it yet, C'MON! Nice work man, it's good to see a proper motor in that car, I can already tell this thing is going to be FAST! Keep up the good work, looks sick!

Ok, so I made some progress today. I ran six more wires from the TCU up to the front of the car, so the wires are all ready for the paddle shifter assembly that I am building tomorrow I think that I might try to get the DCCD knob worked out today or Monday, not sure which, but I should have all the goodies wired in and working by Monday evening! Pics: All ready and waiting for the paddle shifters! I am getting close to wrapping this all up and I am getting all excited to use the paddle shifters!

Well I just looked at my FSM and all it has is the SPFI, and I take it you need the carb version, and I don't have it. Sorry dude

Well, I am glad you made some progress! My system has a hard line that runs across the top of the engine compartment that then connects to a "soft" line, if you have something like that, check it, there could be a crack in the hard line that you can't really see. I would just replace all the vacuum hoses with new just to be on the safe side, that stuff is cheap enough that it really can't hurt. Sounds like you are at least are on the right path!

I would still think that it has something to do with the vacuum or lack thereof. My car had almost the exact same symptoms, and since they are two different types of cruise systems, but they have the same problem, and the only common thing is that they both work off of vacuum, I would suspect the cruise vacuum system. I would try to test to see how much vacuum is in the system at freeway speeds. A little hard to do, but that's the only time you have a problem, so that's when you need to test it. That's where I would spend my time until I ruled out for sure that I have no vacuum leaks at all in the cruise system. Another option is to just get a dealer installed kit like mine and rig it into your car. The system is designed to be installed separately, so it will be easy to install if you can find one. Just a thought.

I don't know anything about the ea81 cruise system I have an ea82, but I take it it's vac controlled? I had this same issueish with my cruise, but it's because I was losing vacuum, so therefore it couldn't hold the speed at freeway speeds, but around town it was fine. So you might want to check for vacuum leaks. If it's like mine, it's got an actuator by the pedal, if you have one of these, is it functioning properly? It could have an internal leak so the system can't hold pressure anymore. Same goes for the control unit for the vacuum system (not the cruise computer, this controls how much vacuum to apply to the pedal actuator itself). Mine is a separate unit, so if it develop an internal leak, it would cause the whole system to lose pressure as well. The computer failing just for high speeds, seems very unlikely. When these systems fail, usually they totally fail, or just a certain function, but since it works at low speeds, that would tell me that the computer is at least sending the signal to do something (this would be the function I was talking about, being able to send a signal), the system is just mechanically not able to do what the computer asked. Though anything is possible when dealing with older computers, they tended to do some funky stuff to make things "work", so the computer could be bad as well, but that would be the last thing I would check. So I would check for vacuum leaks/leaky, loose, broke hoses to startoff, then other suspect parts like the pedal actuator and the actual contol unit for the vac system, and then finally I would think about looking at the cruise computer. Again, assuming it's like mine and vacuum controlled... Hope this helps!

Sorry I haven't posted anything yet, I haven't been able to take a pic... My wife's had the camera and I haven't seen her to get it, but maybe tonight... I hope you worked it out in the mean time though...

I would try mothers back to black. I just used it on my headlight switch that was ash colored and it made it black. Very impressed. It's not a "black" paint like stuff or anything, it just helps return the plastic back to its natural color. The product itself is white, so don't let the name fool you It's good stuff. Cost about $5.

My FSM should work for you. I have to run home here in a few hours, I will snap some pics of the pages and post them up for you!

What year is your car? Like I said, I got an FSM for an 87 that I could take photos of the vac line pages for you if you need, let me know... Congrats on getting the car running!

I think thursday will work, in the morning, after "traffic" clears up should be fine, that is unless you fix it before then of course! I will PM you later today/tonight to confirm/swap info.

Thanks. I am just trying to copy the really smart guy here. This whole project has been a challenge for sure. Let's just say before I started this my soldering skill were adequate to say the least But between soldering in 30 wires for the harness and replacing transistors, I can now remove a 28 pin chip off of a pcb board without messing anything up, so they have improved just a little. It's been alot of fun as well. I have been taking pics along the way to document this, since I am doing it I might was well try to help others. It's good practice to document for my line of work anyways, so I will have lots of pics and I will explain everything once I get it all going. I hope that I can show that someone without a lot of experience can do this sort of thing if you put your mind to it. I am just really persistent and I refuse to let a computer, or a car for that matter, beat me! That's one of the main reasons I like computers, there is always a fix, and a right and wrong. You just need to know how to do it, but it makes finding the answer easier, because you know it exists. Same applies to cars, and that's why I started learning about cars. It either works or it doesn't, there is no in between. Works much better that way

Hey dude, I got a 1990 loyale turbo... so most of it's the same. I can come down and visit ya, but not tomorrow/today whatever day it is. I actually work nights as well so that timing is fine for me, but tonight/today is my long night (I have already been up for 22 hours :-\), but maybe some other time this week? I also have a 87 FSM that might help you out as well if you would like to look at it... Let me know, I really don't have anything going on...

Got the same truck! I love it. I need to replace a screw in the trans on mine, it's only $3 but it's about an hour of labor to replace it, and I just haven't done it yet. That and I need a new fuel tank by now as well I love nitro stuff Now where's all your whirly birds and aeroplanes Controlling things in the air is SOOOOOOO much more fun

Ok, so after I installed the new modded TCU, it started acting up. It would basically reboot itself. I would be driving down the road and all of a sudden the power light and the atf temp light would come on and the car was in 3rd gear locked in 4wd. The TCU had decided it didn't want to work anymore. So after looking at the board some more, and with the help of presslab, I was able to determine that all the electrolytic caps where bad and needed replacing. So that's where I am at with that TCU. Now luckily for me I happen to find yet another TCU with that same part number, this time out of a car that was t-boned, so at least this TCU was functioning before the accident. It arrived in the mail on Saturday, thanks Uberoo!, so I was able to start playing with it. I plugged it in just to see what would happen, and it worked normally! Yay! It worked without any modification! So that meant that this TCU was already in better condition than my previous one. I then removed the solder from the holes to prepare it for a DIP socket. I unfortunately was unable to find a DIP 28 socket, but I got a DIP 40 socket and just trimmed it down to 28 and it that worked out good. I then left it in the stock configuration and test drove it around for two days and about 70 miles just to make sure that it was working before I tired to modify it. After putting it through the crucible, I decided it was time, all or nothing! So after practicing lifting the pins of the stock rom on my other TCU, I set out for some experiments. First I tried running a 10k resistor to pin 22 (OE Output Enable) from 5v, just to make sure that the OE was turned off. Tried it in my car, power light and atf light, so no go. I then lifted the CE (Chip Enable) pin 20, and the OE pin 20, and the same result, double lights. I then lifted the power and the ground for the chip to completely disable the chip, and I still got the double lights. So it was time for this stupid stock ROM to come off! So 30 min later I had the chip removed, I went down to my car, started it up, and the atf light went out, and then shortly after the power light went out as well! This is good. Turned it off tried again hoping for no errors and I got no errors! It seemed to work! After taking it for a test drive for about 20 miles all seems well. It shifts better, and feels more fun to drive. I have not tried out the paddle shifters, but its only running my modded ROM, so i should work fine. I have some caps on order for my other TCU, so when then come in I am going to try to figure out why I HAD to remove the stock ROM in order for my other ROM to work, so that should be fun. I want to be able to switch between the two ROMs, but really that's just to say I did I won't let this stupid thing beat me! This week I will have some time to be able to start running those wires, I have been busy trying to get this TCU to work, and then I will start building the paddle shifter assembly itself. I hope this all starts going smoother from this point forward thats for sure!

Hello all, To start, a shout out to presslab, he really helped me worked through alot of my problems, thanks dude! A while ago I was browsing through this forum, and I came across this awesome thread about building paddle shifters for the 4EAT. Here's the link: http://www.ultimatesubaru.org/forum/showthread.php?t=93670 This was my inspiration. So about the beginning of February I PM'ed presslab to see what really needed to be done and if this was really possible for me to do. I guess I should also give a little background on myself before going any farther. Right now I am training to become a IBM Mainframe systems programmer, I have modded xboxes and other SOC (system on a chip) devices including routers, and I have a good background working with computer systems in general. So this whole car thing is new to me, but not electronics. So with that said... After talking with presslab, I came up with a list of things that needed to happen so that I could get paddle shifters in my loyale. Here's the list: 1. Get TCU 2. Build simple cable to interface with TCU 3. Download original TCU ROM using the cable that I just built and the linux software 4. Compare original TCU ROM Code to new modified ROM code to check for differences to make sure the ROM is compatible and modify any settings 5. Install DIP 28 socket onto TCU PCB 6. Burn new ROM image onto new EEPROM 7. Install new EEPROM into the new DIP socket on the TCU, and disable the original ROM 8. Splice in new plugs into exsisting TCU harness for the new TCU, but keeping the old as a backup 9. Modify the RPM signal going to the new TCU via the new harness. Use a 1k resistor and place it inline from the ECU to the TCU. On the TCU input install a 4.7V zener diode after the resistor with the cathode on the TCU input and the anode to ground. 10. Build the DCCD switch using a six position rotary switch and wire in some 1N4001 diodes in a series between each pole. The FWD switch pole is attached to ground and the common is attached to the atmospheric sensor input. 11. Build the paddle shifter assembly and install it With such a short list, it should take me no time to do it all Needless to say I have spent ALOT of hours just researching and trying to figure out how all this works, and I just got it working today, a month and a half after I started. So this project isn't for the weak hearted, that's for sure! Personally I don't want to modify something in my car, especially anything having to do with the transmission, unless I honestly can understand what has been modified, how it was modified, and why it was modified. Once I can figure all that out, I will feel much more comfortable installing this into my car. So I set out learning assembly code for the Motorola 68CH11 processor. Lucky for me I am already somewhat comfortable in a low level machine language due to my training on the Mainframe, so picking up the assembly wasn't that hard. It wasn't easy, but not that hard. The hardest part is knowing how to read a reference manual Man that crap can put you to sleep! Anyways, once I had figured out the jist of what was going on in the ROM, I set out on getting a TCU that had the same part number has presslabs. Once I found that, I needed to get the harness for the TCU, since the TCU I bought didn't come with the wiring harness. Wiring harness in hand, I set out to wire it up. Here's my thread on the wiring harness: http://www.ultimatesubaru.org/forum/showthread.php?t=110131 I broke this whole process up so that each step I did was more easily searchable, and more organized. Also these posts have a bunch of pics in them, so beware! Read through that thread to see the problems I had with that and how I solved them. Once it was wired in, I then had another problem, the AWD didn't work. I had a fried transistor on the TCU board that I had to replace. Here's my thread on how I fixed that: http://www.ultimatesubaru.org/forum/showthread.php?t=110121 After all the hassles and trouble shooting, trails and tribulations, I was finally able to install the moddified ROM onto the EJ TCU and got it working! Granted I skip a few steps along the way... I had a buddy of mine burn the ROM image for me, so that was already done. I ordered the cable that I need to interface with the TCU, but I am still working on getting the tcuscan software to work for me :-\ I just gave up and moved on. I figured that if it didn't work with the new ROM, then I would have to figure out tcuscan. Since the modified ROM worked, I am not in a hurry to fool around with tcuscan. I will in the future, but for now, it can wait. With that, I have also not downloaded the stock ROM to verify against presslab's ROM, but since it his ROM worked in my TCU, I can assume that the ROM is the same. Here's some pics of adding the new socket on the board, and with the new ROM on the board: Before Modifiing: After: Here's some "action" shots, or something like that... Half done: You can see where I started, and how my soldering skills got better as I went First time I have ever tried doing anything like this. Good times All done: Socket installed: So in order to get the DIP socket to work, you have to move a resistor... You have to move it from 421 to 422. The "000" on the resistor means 0 ohms, so you can just use a piece of wire as well, which is what I ended up doing, since that resistor is a huge PITA to move. I am going to install a switch so that I can flip between the two ROM's whenever I want. This way it makes this mod a little more reversible. To a point anyways At this point since the TCU is functioning "normally" in my car, I am ready to start running more wires for the paddle shifters and dccd knob, as well as the wire for the select monitor, and to start building and adding all the goodies and getting it installed (5 additional wires total). I have the DCCD knob already here, and I have some ideas on the paddle shifter assembly that I should be able to test out here soon, and I should be able to start wiring it all in starting this weekend. My first plan is to install the DCCD knob and get that working, then the paddle shifters. I figure one thing at a time, that way I don't get to overwhelmed, so stay tuned!

Notice something different? I can officially say that I was correct in my previous post. The new ROM("SST" chip) is in and is working perfectly with no errors and no flashing power light :banana: Took him for a drive and everything worked flawlessly. After the drive and during I stopped and checked for power light flashes/errors and... nothing! Woohoo!! Now that it works "normally", time to start adding all the goodies!

Kinda like the motorcycle wave as well. I give the peace sign to passing bikers just to say "Sup!". I like this idea, I will start doing it in the oly area, so lookout my fellow Olyians!

Ok so I wasn't quite happy with my previous answer since I didn't know exactly what was failling so I dug a little bit deeper, and then I found this little handy chart saying what to look for under certain conditions. According to this chart, and it's from a 1995 FSM so things could be different, if front wheel slipage occurs, one of the things to check in VSS2, which would fall into line with what I was saying in my previous post. Since the TCU is recalculating VSS1, it's assuming that VSS1 is correct (it's not in this case, VSS2 is correct because it's not being recalculated, but the TCU doesn't know any better) so when the numbers are off, it defaults to saying the VSS2 is broke because it's giving a false speed reading (since it's different than VSS1), and then it puts the trans into FWD mode because of this. I think that answer all the questions on why my trans is acting the way it is and why the trans is putting itself into FWD mode. Here's the code that I found and if you follow the code for the VSS2 error, it leads to the same chunk of code that handle the FWD fuse, so I can back up this all up with the code. Of course this is assuming that I am reading the code correctly as well First chunk shows the VSS2 Error and FWD fuse functions and where to branch to handle those: E25E loc_E25E: ; CODE XREF: CalcVehicleSpeed+7j[B][COLOR="Red"]E25E brset *errorFlags, $20, loc_E27A ; ' ' ; VSS2 Error[/COLOR][/B][B][COLOR="red"]E262 brset *misc_Inputs, $80, loc_E2C7 ; '€' ; FWD Fuse[/COLOR][/B]E266 cmpb byte_C04BE269 bhi loc_E273E26B ldaa byte_C04EE26E aslaE26F staa byte_AF Here's section E27A (VSS2 Error): E27A loc_E27A: ; CODE XREF: CalcVehicleSpeed+CjE27A ; CalcVehicleSpeed:loc_E25EjE27A ldaa byte_17E27C brset *errorFlags, 4, loc_E2B0E280 ldab byte_C04EE283 stab byte_AFE285 cmpa byte_C04BE288 bhi loc_E2A1E28A cmpa byte_C04C[COLOR="Red"][B]E28D bcs loc_E2C7[/B][/COLOR]E28F ldab VSS2E291 cmpb byte_C04B[B][COLOR="red"]E294 bhi loc_E2C7[/COLOR][/B]E296 bclr *errorFlags, $10E299 bclr *errorFlags0, 2E29C bset *byte_2, 2[B][COLOR="red"]E29F bra loc_E2C7[/COLOR][/B] As you can see (highlighted in red), if it errors in anyway it branches to the FWD Fuse function... And section E2C7 (FWD Fuse): E2C7 loc_E2C7: ; CODE XREF: CalcVehicleSpeed+12jE2C7 ; CalcVehicleSpeed+21j ...E2C7 brclr *errorFlags, 2, loc_E2DFE2CB ldaa VSS2E2CD ldab VSS1E2CF brclr *byte_30, 8, loc_E2D8E2D3 bclr *errorFlags, 2E2D6 bra loc_E336 So at this point, the code is running the same branch instructions (to location E336), so it's the same for the VSS2 error, and the FWD fuse. So I think this gives us a solid answer as to why this problem is solved via software and why tire size and diff ratio actually matter when dealing with calculating the AWD. If I am wrong on this, someone please correct me!

Ok, so after reading what Chux said, I decided to dive into the code to try to figure out what the hell was going on. Here's the two parts of the code that calculate the 2 speed sensors, VSS1, and VSS2: Calc VSS1: D6ED CalcVSS1: ; CODE XREF: SPIE-1044PD6ED ; SPIE-FB5PD6ED ldd word_24D6EF std word_1BD6F1 ldx #gearRatioMapD6F4 ldab currentGearD6F6 aslbD6F7 abxD6F8 ldaa 1,xD6FA ldab word_1B+1D6FC mulD6FD tabD6FE clraD6FF std byte_BBD701 ldaa 1,xD703 ldab word_1BD705 mulD706 addd byte_BBD708 std byte_BBD70A ldaa 0,xD70C ldab word_1B+1D70E mulD70F addd byte_BBD711 std byte_BBD713 ldaa 0,xD715 ldab word_1BD717 mulD718 tbaD719 clrbD71A addd byte_BBD71C std inputShaftRPMD71E ldd word_26D720 lsldD721 lsldD722 std word_1B[SIZE="3"][COLOR="Red"][B]D724 ldaa VSS1toKPHconst ; (862 * 4.11) / (899 * 3.7) * 0xE2 = 0xEF[/B][/COLOR][/SIZE]D727 ldab word_1B+1D729 mulD72A tstbD72B bpl loc_D72ED72D incaD72ED72E loc_D72E: ; CODE XREF: CalcVSS1+3EjD72E tabD72F clraD730 std byte_BBD732 ldaa VSS1toKPHconstD735 ldab word_1BD737 mulD738 addd byte_BBD73A std byte_BBD73C lsldD73D bcs loc_D745D73F lsldD740 bcs loc_D745D742 lsldD743 bcc loc_D74AD745D745 loc_D745: ; CODE XREF: CalcVSS1+50jD745 ; CalcVSS1+53jD745 ldaa #$FFD747 bset *byte_30, 1D74AD74A loc_D74A: ; CODE XREF: CalcVSS1+56jD74A staa VSS1D74C rtsD74C ; End of function CalcVSS1D74C Calc VSS2: DFFB CalcVSS2: ; CODE XREF: SPIE-1041PDFFB ; SPIE-FB2PDFFB tst byte_AEDFFE bne loc_E006E000 clraE001 clrbE002 std word_1DE004 staa VSS2E006E006 loc_E006: ; CODE XREF: CalcVSS2+3jE006 brclr *byte_2F, 1, locret_E061E00A bclr *byte_2F, 1E00D tst byte_AEE010 beq loc_E05CE012 seiE013 ldaa byte_2DE015 staa byte_BCE017 ldd byte_2BE019 cliE01A ldx #2E01DE01D loc_E01D: ; CODE XREF: CalcVSS2+2AjE01D asl byte_BCE020 rolbE021 rolaE022 bcs loc_E029E024 dexE025 bne loc_E01DE027 bra loc_E02CE029E029 loc_E029: ; CODE XREF: CalcVSS2+27jE029 ldd #$FFFFE02CE02C loc_E02C: ; CODE XREF: CalcVSS2+2CjE02C std byte_BBE02E xgdxE02F cpx word_C012E032 bls locret_E061E034 ldd word_C012E037 fdivE038 stx word_1DE03A addd word_C014E03D ldx byte_BBE03F idivE040 xgdxE041 addd word_1DE043 std word_1DE045 ldd word_C016E048 ldx byte_BBE04A idivE04B xgdxE04C tstaE04D beq loc_E054E04F ldab #$FFE051 bset *byte_30, $10E054E054 loc_E054: ; CODE XREF: CalcVSS2+52jE054 addb VSS2E056 rorbE057 stab VSS2E059 bset *byte_30, 8E05CE05C loc_E05C: ; CODE XREF: CalcVSS2+15jE05C ldaa byte_C018E05F staa byte_AEE061E061 locret_E061: ; CODE XREF: CalcVSS2:loc_E006jE061 ; CalcVSS2+37jE061 rtsE061 ; End of function CalcVSS2 As you can see, VSS1 is recalculated, and VSS2 is untouched. I have highlighted in red the important part of VSS1, the part that recalculates VSS1 to read the same as VSS2. So what I found out is that the TCU has to take the input from VSS1 and then recalculates it so that it matches VSS2 in order to figure out if slip is occurring (DUH!). So it has nothing to do with the tire size directly, but how the TCU recalculates the VSS1 speed to make sure that it MATCHES what the VSS2 should be so that the two sensors are reading the same speed in order to calculate slip correctly. Now this makes total sense. So then if VSS1 and VSS2 are reading different numbers (they are reading two different numbers because the VSS1 is being recalculated for the EJ tire size and 4.11 rear diff, not the EA tire size and the 3.7 rear diff (I don't think that the rear diff matters, but it could), and VSS2 is not being touched so it's the actual speed the car is traveling, while VSS1 is recalculated based off what the tire size should be coming from the factory, and the factory rear diff ratio for the car) the AWD will not be able to calculate the amount of slip correctly, and then it faults, putting it into FWD mode. Basically it runs the calculations on both speed sensors and then compares VSS1 and VSS2, which should be the same, and if they are not, it throws out an error which then affects the AWD. The rest of the system is fine, since none of the other components require a direct comparison of the 2 speed senors in order to function properly, it's either one or the other. So I believe that's why I am having the problems that I am having, and also why changing that one variable in the software fixes everything right up. Does that all make sense? Chux: Thanks for the info man! I didn't know all of that before, so thanks for that!

I think you hit the nail on the head here with this. If I remember reading correctly the legacy speedo is controlled by the TCU? Or something to that affect. The TCU somehow influences the speedo in the legacy's, I believe. I think I remember reading something like that. I am too tired right now to research this, but I will tonight when I get up. But I think that this is where the TCU comes into play and why changing that one variable fixed it for presslab and hopefully me. Even though the TCU doesn't control my speedo, the sensor that does control it might have to be calibrated, and that's where the software comes into play. Do keep in mind that I am only going off of what someone else has done, and my reading of the code and understanding of the code. Presslab said that he changed one variable in the ROM when his trans was acting like mine, and then all was well, and he hasn't had a problem since. I have the chip in front of me with the moddified ROM burned on it already , the DIP socket, and the solder holes clear on the board, so it will be as simple as "throwing it in" to see if it works or not, then I will be able to tell for sure I am just trying to get my ducks in a row before I dive in, so one could say I have a pretty good handle on it... The important part was making sure the TCU actually worked and that also ended up being the hardest part :-\ I don't know much about OBD II at all so ya. I do know that in an OBD II trans there are more signals going to and from the TCU to the ECU, but not in mine. That's a Phase II 4EAT if I remember correctly... There is only 1 input from the ECU and that's for RPM on the Phase I, but I am sure you already knew that. So there are some differences, but I don't know enough about them to be able to say anything about it... Right now I am having trouble getting the tcuscan software to work, but I am to tired to care, so I will look at it some more soon. So once I can manage that and confirm that my wiring is correct via the tcuscan software (I think it is already, but I like to double check), then it's off to the fun part of the project

Congrats on making it home! It just seems like something was bound and determined to not let you get that car home! Glad it's fixed man.

Don't be fooled by the name TOD (tick of death), the tick is fine. They can tick all day and never hurt the motor, or so I have been told anyways... Mine does the same thing on startup, and I am not worried about it at all. Sometimes I will add some MMO (Marvel Mystery Oil) and it seems to help with sir ticks alot, but I don't add that alot of the time. I have notice that when my oil gets low it will tick more, but other than that i wouldn't really worry about it. I drive from Olympia to Seattle and back every weekend and have racked up about 10,000 miles since I got my tickin' subie and I have had no problems at all. You can replace the pump, but just for a little tick, I wouldn't fuss about it until something else comes up and you need to dive in a replace the oil pump since if you replace the pump you might as well do the water pump and the t-belts as well since you are in there. It's kinda a big job. As for seafoam, just do a search for it. There are tons of threads about how to use it. I use 10-40w chevron oil and don't plan on changing that anytime soon I don't really think there is a need to run synthetic, but to each their own. I think that just about answers your questions, good luck!

Sad times But I think you get the idea of where this is all heading, it was probably the same thing that you wanted to do... Ok, you got me. It's not truly JUST the rear diff. The TCU actually expects the tire/rim size to be a certain size and rotate at a certain revolutions per minute while the car is traveling at 60mph. So for the EJ cars, it expects E2 in hex, or 226rpm at 60mph. For the EA cars it needs EF, or 239rpm at 60mph. So it works out to be about 6% difference, just in the tire size, and that doesn't include the 3.7 rear diff which throws things off as well. So I think that is why you can switch trans' with the EJ series (SVX, Legacy, Impreza) with no problems and without switching the TCU, but when you try to move things across to the EA series, you run into a little more problems concerning tire/wheel size. The XT's might be different as well since they have 5 lug, but I really don't know, I haven't looked into that. But I think this is the main reason for the AWD not working. Now I also know that Gloyale swapped in a EJ trans into his EA car, but kept the EA TCU and all is well, so ya. I haven't looked at the code on the EA TCU to see the differences but obviously that works fine, but you are keeping the wheel size the same for the most part (EA wheels with EA TCU). It could also be that the code is completely different and more forgiving about the tire/wheel size as well, but I don't know since I have not seen the ROM code, so that is just speculation. It would make sense though because the XT's are 5 lug, so they probably just used the same TCU and made the code more forgiving, and then locked it down more with the legacy revision. Again speculating, but it would make sense. As it sits right now, when I start the car twice to check for errors, I get no errors, but as soon as I go for a drive, I get an error the next time I try to start it, so something is going on after the car starts moving, which falls in line with what presslab said his was doing before modifying that variable from E2 to EF. Once he changed that variable in the ROM, the AWD starting working again. The next step that I am going to do is to interface with the TCU via the alcyone.org linux software tcuscan while it's running and really see what's going on. I have the cable made already, I just need to get the actual TCU to function "properly" before I tried doing anything else to it, which I have finally succeeded in doing, so I will probably get to this in the morning. Once I get that done I will be able to tell what is really going on with the TCU and to see if all my sensors are working the way they should. Everything else in the car functioned properly on my test drive, just not the AWD. But the tcuscan software should be able to tell me if everything is good or not. At least I hope so

For those of you who are curious, I have created a thread showing how I made the harness to fit an EJ TCU into an EA car (4EAT). Here's the thread: http://www.ultimatesubaru.org/forum/showthread.php?p=910845#post910845 This was good times for sure :-\