Rear Locker + ATRAC - Write up

Tankota · 08-15-2006, 08:39 PM

***Updates***
The TRD edition has this working already from the factory.

Seems all the newer FJ's released after the TRD edition now have it working without the modification.

Also, here's a nice write up on doing the mod anotherway without cutting the wire in the engine compartment.

**End Updates***

Ok, it's been finaly done!

A BIG BIG BIG thanks to Alex H., he did all the study and theory behind it, working with the elec diagrams and logic flow of the FJ's systems - and he doesn't even have an FJ!! . I'm just the lab rat who was crazy enough to try it first. So yes, I now can have both the ATRAC system and the rear locker on at the same time, or just ATRAC, or just rear locker, or none of the above.

Ok, on to how to do it!!.. First off, do this at your own risk, yes this could void your warranty, no don't do it if you have no idea what you are doing, and nobody is responsable if you screw it up or anything else!! But if you want to use the rear locker and ATRAC at the same time, read on!

This is the master cylinder, with the VSC computer on the side of it. For those with service manuals and/or electrical diagrams for the FJ, the large connector with all the wires is A4, the smaller one is A5.

This is the wire you are looking for - it's the SMALL blue/yellow. It's pin 26 on the connector, in the electrical diagrams it's terminal EXI3.

You want to cut the blue/yellow, leaving a good amount of length. You then want to take the connector side of the blue/yellow, and using a T-junction or tap, connect it to the Black/orange wire on connector A5 (pin 1). You do not want to cut the black/orange, just tap into it. The remaining blue/yellow in the wire harness just tie away inside the harness, do not ground it or connect it to anything.

That's it! You now can use ATRAC with the rear locker. Damn that was simple wasn't it?

Ok, the theory behind it (all via Alex). The blue/yellow wire is a signal wire from the rear locker (actualy it's from the dash light circut). When the locker is off, this wire has +12v, telling the VSC computer that the locker is off and it can use ATRAC. When the locker is locked, this wire has 0v, telling the system the locker is locked and then it won't let ATRAC turn on. All we have done is take the wire, and tap it into the 12V acc power on connector A5. This tells the VSC computer that the locker isn't on, all the time, even when the locker is on. This doesn't affect the locker light or any of the other lights or system. It just fools the VSC computer into thinking the locker is off all the time.

In Alex's honor, for all his work on this, I think we should call this the Alex hack!

JohnGalt · 08-15-2006, 08:49 PM

The AWM!!! Wowza - AlexAtracHack

sbechtold · 08-15-2006, 08:59 PM

Very cool mod. When are you going to test it on the trails? Do you have any concerns about ATRAC trying to apply the brakes to one wheel on a locked axle? I wish we knew more detail about how ATRAC works.

Tankota · 08-15-2006, 09:11 PM

Quote:

Originally Posted by sbechtold

Very cool mod. When are you going to test it on the trails? Do you have any concerns about ATRAC trying to apply the brakes to one wheel on a locked axle? I wish we knew more detail about how ATRAC works.

ATRAC works by sensing wheel spin on each axle. If it senses one wheel on an axle spining faster than the other, it applies brake to that wheel to lock it and transfer the power to the other wheel. Since the rear is locked, one wheel on that axle can't spin at a diffrent speed than the other, so the ATRAC system never activates on that axle, it ignores it. It will then only activate on the front if it senses one wheel spining up there.

Toyota ran an FJ on the Rubi with a simular mod, and rumor has it they may enable this on the 08's

Tankota · 08-15-2006, 09:27 PM

For some background history of how this mod came about, it orginated on the mud board:

http://forum.ih8mud.com/showthread.php?t=84238

Alex I already personaly knew from wheeling with him as part of The Trail Crew. We e-mailed back and forth the details of trying this mod, including wiring and electrical diagrams.

treknwil · 08-15-2006, 09:59 PM

In the FJ cummunity this is like the second coming of Christ.

FJ Cruiser News · 08-15-2006, 10:16 PM

Hats off and a decent bow to the electrical wizards whom can look at scematics and figure this stuff out. IRL I am a plumbing contractor, Union
trained, 15 years old to 48 years old, I need no more practice, I have always held men whom can grasp scemantics of electrical systems and design to the highest level of intelligence. When it comes to electricity, I RUN, and dam fast at that!

I am 99.9% sure that if I were to do this w/ the warranty policy I purchased, that covers much of the electronics on the vehicle, basically I bought (some will say threw away big money) a 1600 $ or so policy covering dam near everything. Oh well, I am very impressed w/ your skills though. Congrats!

Tankota · 08-15-2006, 11:06 PM

Quote:

Originally Posted by treknwil

In the FJ cummunity this is like the second coming of Christ.

Donations can be sent via pay-pal to vaud "at" cyberverse.com

I need a set of 17" Mojave Teflons so I can fit 34's. LOL..

Tankota · 08-16-2006, 07:24 AM

Ok, it's been tested on an MT and works on them too, make sure your taps into the black/orange are good! Same person also took it off-road and verifed the ATRAC and locker are working with no problems.

viter · 08-16-2006, 08:38 AM

nice!!!

Hotrodguru · 08-30-2006, 05:24 AM

Posted this on the FJ Cruiser Forum

PROOF that this mod is a BIG advantage.

http://www.fjcruiserforums.com/forum...ead.php?t=8917

Chris has the mod on his FJ, tackling this hill was not the easiest thing with our stock FJ's but Chris's did it alot easier than mine. I had to stop and keep switching between ATRAC and the locked rear diff. The process was repeated many times while Chris just gave it gas on the same climb and made it to the top on the first go run. I did too, but after alot of switching around. Can't wait to do this mod.

Guru

Strike · 09-02-2006, 10:43 PM

I did it. Works great. It only takes 5 minutes. It's not worth it Not to do it IMO.

highbeams · 09-03-2006, 01:58 AM

Tankota and a few guys from 2 other forums gave the mod a major workout yesterday at Rowher Flats, and came away all smiles and thumbs up.
as they said, it works perfectly, giving you a locker in the rear and a computerized limited slip in the front. doesn't get better than that.

yoshiboy · 09-05-2006, 12:39 AM

Looking at the picture above, does he have stock tires? It looks like just Dueler HTs. I was just wondering.

rfjtoy · 09-05-2006, 11:34 PM

I went up Miller's Truck Trail yesterday, a-trac and rear locked. The tractions was great and it patched worked great all day LOOOOOOOng.

Interex · 09-06-2006, 06:03 AM

Quote:

Originally Posted by yoshiboy

Looking at the picture above, does he have stock tires? It looks like just Dueler HTs. I was just wondering.

Yes, he was running stock wheels/tires.

calamaridog · 09-06-2006, 08:02 AM

The combination of TRAC and rear locker is awesome. The 2000+ Land Cruisers have TRAC and run this combination with a rear ARB. Very nice to have options such as this and I'm not surprised to see Tankota leading the way. Sweet.

Hotrodguru · 09-19-2006, 01:11 PM

Well finally had the chance to try out the mod this weekend and I'm going to have to give it a big thumbs up! At the crest of this climb was a nasty drop off to the left. Since the conditions were muddy and slippery the vehicle would naturally slide down to the left towards some trees. On the right side the front right tire would catch some big roots which meant there was not grip to be had.

Well after some careful manuevering back and forth I was able to shimmy outta the bind. With the rear locker locked and A-TRAC off the front tires would spin with no grip. As soon as I enable A-TRAC I was able to progress forward enough that I could change my approach angle and get out of that tight bind. Once I was facing the direction I wanted to go I turned off the A-TRAC. I wanted some tire spin and a bit more speed to get out...worked like a champ.

KungFooo · 09-19-2006, 09:12 PM

I really want to do this mod, but at the same time I am affraid to cut into the wire.

DigableKid · 09-25-2006, 02:07 AM

Did it, works great. Good lookin out Tankota and all affiliated!

PWWFJ · 09-25-2006, 04:17 AM

Another THANKS to Alex and Tankota. I did it also and works great. Yeee Haww!

OFRD_GRL · 09-26-2006, 10:29 AM

provided its not raining this evening i will be doing this along with finally wiring my winch and putting in my rope line

LandCruisers4Life · 11-18-2006, 05:49 PM

If and when I do this mod.. Probably WHEN I do this mod, I will be making it to where I can switch it back and forth from stock to modified wiring configuration, and at the same time using some sort of waterproof connectors (marsh marine probably). That way if the Toyota tech plugs in his computer to do diagnostics he will not detect any difference. In other words, keep the wiring in modified form for everyday driving until you take it to the dealer, then switch it back to the initial configuration so Toyota isn't any wiser.

SAR_Squid79 · 11-19-2006, 09:17 AM

NICE JOB!

You should print up some professional looking instructions, make up some of those jumper wires and sell this as a kit on eBay for $25 a pop!!

hytenor · 11-19-2006, 12:59 PM

Toyota will be offering this with a new TRD pkg...for around $7500 extra. Your mod seems like a slightly more economical solution, LOL

FJAggie07 · 11-19-2006, 01:41 PM

I have done this mod and it is invaluable. Nough said.

Tankota · 11-19-2006, 10:25 PM

Quote:

Originally Posted by hytenor

Toyota will be offering this with a new TRD pkg...for around $7500 extra. Your mod seems like a slightly more economical solution, LOL

I still think they stole my write up for the TRD edition.. we should be getting some of that TRD package money.. lol...

hytenor · 11-19-2006, 11:52 PM

Quote:

Originally Posted by Tankota

.. we should be getting some of that TRD package money.. lol...

Tankota · 12-29-2006, 11:35 AM

Minor updates added to post #1.

hytenor · 12-29-2006, 11:50 AM

Quote:

Originally Posted by Tankota

Minor updates added to post #1.

so, when do you do the crawler mod?

08-15-2006, 08:49 PM	#2
JohnGalt Newbie Join Date: Jul 2006 Posts: 1	The AWM!!! Wowza - AlexAtracHack Last edited by JohnGalt; 08-15-2006 at 08:52 PM.

08-15-2006, 09:27 PM	#5
Tankota Primordial Member Join Date: Dec 2004 Location: Reseda, CA Posts: 523	For some background history of how this mod came about, it orginated on the mud board: http://forum.ih8mud.com/showthread.php?t=84238 Alex I already personaly knew from wheeling with him as part of The Trail Crew. We e-mailed back and forth the details of trying this mod, including wiring and electrical diagrams. __________________ David Hale Bright Ass Yellow 2007 Toyota FJ Cruiser:Project T2 Icon 2.5" reservoir shocks front and rear, Icon UCA and rear links, 34" Goodyear MT/R tires, Demello Off-road front and rear bumpers, sliders, and skids, 4x150W roof mounted KC's and safari lights, and my ATRAC-Hack 2007 Yamaha Grizzly 700fi 4x4 2007 Toyota Yaris S-Sedan (DD) http://www.TheDirtyLens.com http://www.offroadingadventures.com/

08-15-2006, 09:59 PM	#6
treknwil Senior Member Join Date: Aug 2005 Location: nor-cal Posts: 118	In the FJ cummunity this is like the second coming of Christ. __________________ 2007 FJ Cruiser 4x4...Yellow and White. A-trac, rear differential lock, Upgrade package #2 with 17" alloys. 285/70-17 MTR's, Home made level lift, Rock sliders, LCA skides, All-Pro extreme LCA links, Home made Highlift jack clamps, 4 KC's on roof rack, 1987 4runner SR5 22RE 5spd. Budbuilt skids & transf. case cross member, Flowmaster. 32x11.50/15 BFG MT's, home made 1" body lift, sliders, winch plate. Had a 81 PU SR5 4x4 long bed brand new as my first new vehicle.... loved that truck!

08-15-2006, 10:16 PM	#7
FJ Cruiser News Banned Join Date: Jul 2006 Location: Monrovia, CA Posts: 9	www.fjcruiser.cc/forum Hats off and a decent bow to the electrical wizards whom can look at scematics and figure this stuff out. IRL I am a plumbing contractor, Union trained, 15 years old to 48 years old, I need no more practice, I have always held men whom can grasp scemantics of electrical systems and design to the highest level of intelligence. When it comes to electricity, I RUN, and dam fast at that! I am 99.9% sure that if I were to do this w/ the warranty policy I purchased, that covers much of the electronics on the vehicle, basically I bought (some will say threw away big money) a 1600 $ or so policy covering dam near everything. Oh well, I am very impressed w/ your skills though. Congrats!

08-16-2006, 07:24 AM	#9
Tankota Primordial Member Join Date: Dec 2004 Location: Reseda, CA Posts: 523	Ok, it's been tested on an MT and works on them too, make sure your taps into the black/orange are good! Same person also took it off-road and verifed the ATRAC and locker are working with no problems. __________________ David Hale Bright Ass Yellow 2007 Toyota FJ Cruiser:Project T2 Icon 2.5" reservoir shocks front and rear, Icon UCA and rear links, 34" Goodyear MT/R tires, Demello Off-road front and rear bumpers, sliders, and skids, 4x150W roof mounted KC's and safari lights, and my ATRAC-Hack 2007 Yamaha Grizzly 700fi 4x4 2007 Toyota Yaris S-Sedan (DD) http://www.TheDirtyLens.com http://www.offroadingadventures.com/

08-15-2006, 08:39 PM	#1
Tankota Primordial Member Join Date: Dec 2004 Location: Reseda, CA Posts: 523	Rear Locker + ATRAC - Write up *Updates* The TRD edition has this working already from the factory. Seems all the newer FJ's released after the TRD edition now have it working without the modification. Also, here's a nice write up on doing the mod anotherway without cutting the wire in the engine compartment. End Updates* Ok, it's been finaly done! A BIG BIG BIG thanks to Alex H., he did all the study and theory behind it, working with the elec diagrams and logic flow of the FJ's systems - and he doesn't even have an FJ!! . I'm just the lab rat who was crazy enough to try it first. So yes, I now can have both the ATRAC system and the rear locker on at the same time, or just ATRAC, or just rear locker, or none of the above. Ok, on to how to do it!!.. First off, do this at your own risk, yes this could void your warranty, no don't do it if you have no idea what you are doing, and nobody is responsable if you screw it up or anything else!! But if you want to use the rear locker and ATRAC at the same time, read on! This is the master cylinder, with the VSC computer on the side of it. For those with service manuals and/or electrical diagrams for the FJ, the large connector with all the wires is A4, the smaller one is A5. This is the wire you are looking for - it's the SMALL blue/yellow. It's pin 26 on the connector, in the electrical diagrams it's terminal EXI3. You want to cut the blue/yellow, leaving a good amount of length. You then want to take the connector side of the blue/yellow, and using a T-junction or tap, connect it to the Black/orange wire on connector A5 (pin 1). You do not want to cut the black/orange, just tap into it. The remaining blue/yellow in the wire harness just tie away inside the harness, do not ground it or connect it to anything. That's it! You now can use ATRAC with the rear locker. Damn that was simple wasn't it? Ok, the theory behind it (all via Alex). The blue/yellow wire is a signal wire from the rear locker (actualy it's from the dash light circut). When the locker is off, this wire has +12v, telling the VSC computer that the locker is off and it can use ATRAC. When the locker is locked, this wire has 0v, telling the system the locker is locked and then it won't let ATRAC turn on. All we have done is take the wire, and tap it into the 12V acc power on connector A5. This tells the VSC computer that the locker isn't on, all the time, even when the locker is on. This doesn't affect the locker light or any of the other lights or system. It just fools the VSC computer into thinking the locker is off all the time. In Alex's honor, for all his work on this, I think we should call this the Alex hack! __________________ David Hale Bright Ass Yellow 2007 Toyota FJ Cruiser:Project T2 Icon 2.5" reservoir shocks front and rear, Icon UCA and rear links, 34" Goodyear MT/R tires, Demello Off-road front and rear bumpers, sliders, and skids, 4x150W roof mounted KC's and safari lights, and my ATRAC-Hack 2007 Yamaha Grizzly 700fi 4x4 2007 Toyota Yaris S-Sedan (DD) http://www.TheDirtyLens.com http://www.offroadingadventures.com/ Last edited by Tankota; 12-29-2006 at 11:39 AM.

08-15-2006, 08:59 PM	#3
sbechtold SAC'D FJC Join Date: May 2006 Location: San Jose, CA Posts: 758	Very cool mod. When are you going to test it on the trails? Do you have any concerns about ATRAC trying to apply the brakes to one wheel on a locked axle? I wish we knew more detail about how ATRAC works.

08-16-2006, 08:38 AM	#10
viter Veteran Member Join Date: Dec 2004 Location: SD, ca Posts: 722	nice!!!

08-30-2006, 05:24 AM	#11
Hotrodguru Senior Member Join Date: Jul 2006 Location: Houston, TX Posts: 228	Posted this on the FJ Cruiser Forum PROOF that this mod is a BIG advantage. http://www.fjcruiserforums.com/forum...ead.php?t=8917 Chris has the mod on his FJ, tackling this hill was not the easiest thing with our stock FJ's but Chris's did it alot easier than mine. I had to stop and keep switching between ATRAC and the locked rear diff. The process was repeated many times while Chris just gave it gas on the same climb and made it to the top on the first go run. I did too, but after alot of switching around. Can't wait to do this mod. Guru

09-02-2006, 10:43 PM	#12
Strike Newbie Join Date: Jul 2006 Location: Las Vegas, NV Posts: 16	I did it. Works great. It only takes 5 minutes. It's not worth it Not to do it IMO. __________________ 2007 Toyota FJ Cruiser Black Diamond MT 4x4 Rear Locker ATRAC Mod 285/75R/16 Goodyear Wrangler MT/Rs OME 3" Suspension Kit More Mods to come as time and money allow.

09-03-2006, 01:58 AM	#13
highbeams Member Join Date: Jul 2006 Location: SoCal Posts: 92	Tankota and a few guys from 2 other forums gave the mod a major workout yesterday at Rowher Flats, and came away all smiles and thumbs up. as they said, it works perfectly, giving you a locker in the rear and a computerized limited slip in the front. doesn't get better than that. __________________ Ten fingers, Ten toes www.adventure4x4.net

09-05-2006, 12:39 AM	#14
yoshiboy Newbie Join Date: Sep 2006 Posts: 2	Looking at the picture above, does he have stock tires? It looks like just Dueler HTs. I was just wondering.

09-05-2006, 11:34 PM	#15
rfjtoy Newbie Join Date: Aug 2006 Location: Laguna Niguel, Calif. Posts: 21	I went up Miller's Truck Trail yesterday, a-trac and rear locked. The tractions was great and it patched worked great all day LOOOOOOOng. __________________ FJC Silver, ARB/Warn 8000, OME lift, IPF lights, 295 Nitto Grapplers, Dirty Parts= Video frt/rear, Street pilot 2720 GPS, Dual Battery, Cobra CB, CO2, ARB freezer/fridge, Atrac patch

09-06-2006, 08:02 AM	#17
calamaridog Veteran Member Join Date: Dec 2004 Posts: 598	The combination of TRAC and rear locker is awesome. The 2000+ Land Cruisers have TRAC and run this combination with a rear ARB. Very nice to have options such as this and I'm not surprised to see Tankota leading the way. Sweet. __________________ 2000 UZJ100 Land Cruiser TLCA #14734 Blue Ribbon Coalition #36400 Calamaridog

09-19-2006, 01:11 PM	#18
Hotrodguru Senior Member Join Date: Jul 2006 Location: Houston, TX Posts: 228	Well finally had the chance to try out the mod this weekend and I'm going to have to give it a big thumbs up! At the crest of this climb was a nasty drop off to the left. Since the conditions were muddy and slippery the vehicle would naturally slide down to the left towards some trees. On the right side the front right tire would catch some big roots which meant there was not grip to be had. Well after some careful manuevering back and forth I was able to shimmy outta the bind. With the rear locker locked and A-TRAC off the front tires would spin with no grip. As soon as I enable A-TRAC I was able to progress forward enough that I could change my approach angle and get out of that tight bind. Once I was facing the direction I wanted to go I turned off the A-TRAC. I wanted some tire spin and a bit more speed to get out...worked like a champ. Last edited by Hotrodguru; 09-19-2006 at 01:21 PM.

09-19-2006, 09:12 PM	#19
KungFooo Senior Member Join Date: Sep 2005 Location: Oceanside, CA Posts: 427	I really want to do this mod, but at the same time I am affraid to cut into the wire. __________________ 2010 4Runner SR5 with stock everything

09-25-2006, 02:07 AM	#20
DigableKid Newbie Join Date: Aug 2006 Location: Oceanside, So Cal Posts: 9	Did it, works great. Good lookin out Tankota and all affiliated! __________________ It's all about Balance and Options Baby.

09-25-2006, 04:17 AM	#21
PWWFJ Newbie Join Date: Sep 2006 Location: Temple Terrace Posts: 5	Another THANKS to Alex and Tankota. I did it also and works great. Yeee Haww!

09-26-2006, 10:29 AM	#22
OFRD_GRL save the bewbies! Join Date: May 2006 Location: Aurora, CO Posts: 4,295	provided its not raining this evening i will be doing this along with finally wiring my winch and putting in my rope line __________________ ~Una My Trucks \| Wheeling

11-18-2006, 05:49 PM	#23
LandCruisers4Life Newbie Join Date: Nov 2006 Posts: 1	If and when I do this mod.. Probably WHEN I do this mod, I will be making it to where I can switch it back and forth from stock to modified wiring configuration, and at the same time using some sort of waterproof connectors (marsh marine probably). That way if the Toyota tech plugs in his computer to do diagnostics he will not detect any difference. In other words, keep the wiring in modified form for everyday driving until you take it to the dealer, then switch it back to the initial configuration so Toyota isn't any wiser.

11-19-2006, 09:17 AM	#24
SAR_Squid79 SoCal Vice Pres. Join Date: Apr 2005 Location: San Diego, CA Posts: 5,203	NICE JOB! You should print up some professional looking instructions, make up some of those jumper wires and sell this as a kit on eBay for $25 a pop!! __________________ ~Jamie 2000 Tacoma TRD 4WD PreRunner Supercharged. Locked. Armored. Mountain: She can crawl it. Ass: She can haul it. *"Roads? Where we're going we don't need . . . roads."* ~Dr. Emmett L. Brown My Rig My Trailer 4xInnovations

11-19-2006, 01:41 PM	#26
FJAggie07 Senior Member Join Date: Nov 2006 Location: Dallas Posts: 306	I have done this mod and it is invaluable. Nough said.

12-29-2006, 11:35 AM	#29
Tankota Primordial Member Join Date: Dec 2004 Location: Reseda, CA Posts: 523	Minor updates added to post #1. __________________ David Hale Bright Ass Yellow 2007 Toyota FJ Cruiser:Project T2 Icon 2.5" reservoir shocks front and rear, Icon UCA and rear links, 34" Goodyear MT/R tires, Demello Off-road front and rear bumpers, sliders, and skids, 4x150W roof mounted KC's and safari lights, and my ATRAC-Hack 2007 Yamaha Grizzly 700fi 4x4 2007 Toyota Yaris S-Sedan (DD) http://www.TheDirtyLens.com http://www.offroadingadventures.com/

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