2003 Subaru Legacy VW Wiring Harness Conversion

[@craigross5945]

I want to add to this. I've done a few Subi-swap harnesses and I'm an electrical engineer. First and foremost, Pick an easy year like 2003-2005 and don't get a California spec computer (You can use one but its a PITA because its much more sensitive to emissions control and will throw more codes). Don't cut any wires for the two main engine plugs and O2 sensors. shorten the wires for both relays. like 12" from the ECU. do not route the O2 sensor wires near anything! They are super sensitive to noise even with the shielding. PICK A GOOD CODE KILLER BOARD! The Smallcar old board is the bare minimal but will still not eliminate some codes. Don't forget to default your computer to manual transmission or you won't be able to start the car. find a way to hook up a neutral switch. The computer needs to see the transmission in neutral once and a while to eliminate the code and also some year ECU's will not kill the injectors when you come off the throttle and shift resulting in a rev-hang (Depressing the clutch will cause RPM's to rise a bit in between shifts) and some ECU's will cause the RPM's to fall to fast and too low coming to a stop. This might stall the van or cause the oil pressure light to illuminate due to low RPM/potential stall condition. it will drive you nuts figuring it out. I'm researching an in-line clutch pressure switch to ground this wire to produce a "Clutch/neutral" signal. make sure your VSS (if you are using a Hall effect ring on the rear CV) is shielded and away from all other wires. This is a super low voltage signal that will cause erratic performance with no warning if the pulses get noisy. Verify with your OBD2 in live data looking at the vehicle speed while driving. Make sure the voltage leads for the O2 sensor heater circuits are not energized when the vehicle is off. A common wiring mistake resulting in a dead battery after 12-24 hours. ONLY use Densu sensors!!! eBay bought sensors are all miss-wired and can or will cook your computer in 2 seconds. Don't wire hour computer to not receive constant 12V battery voltage when key out. There is a wire that needs 12V all the time. Not wiring this up will make the computer "Forget" the learned maps and this might or will be revealed as a double-start condition (start the van, it dies in 2 seconds, start again, runs fine). for experimenters: Some ECU's can almost ignore no VSS signal but need a regular "pulse" to keep the engine happy. I have heard of people wiring up cheap adjustable flasher relays off eBay set to 130 flashes per minute or so. The computer does not use actual vehicle speed to adjust the maps. it seems to only want to know if the vehicle is moving or not. Anyone want to work on this? DO NOT BUY THE SMALLCAR WIRING CHEAT SHEET. BIG WASTE OF MONEY AND ITS USUALY WRONG. ONLY USE 3M ELECTRICAL TAPE. NO EXCEPTIONS AT ALL. TRUST ME. CLEAN ALL CRAP OF WIRES WITH PURPLE POWER! USE GLOVES AND A MASK. TRUST ME. IF YOU SOLDER ANY WIRES, PLACE A SCRAP CUTTING OF WIRE INSULATION OF THE SAME GUAGE PARALLEL WITH THE SOLDER JOINT PLUS 1/2-1" PAST EACH END THEN HEAT SHRINK. YOU NEED THE FLEX PROTECTION. USE A GOUND TERMINAL STRIP INSTEAD OF ROUTING 8 WIRES TO GOUNDS. THE MASTER GROUND CABLE SHOULD BE 8 GUAGE TO ENGINE BARE METAL LIKE THE ALTERNATOR MOUNTING BOLT. DONT USE THE SUBARU OBD2 PLUG. IT SUCKS ONCE YOU DEINSTALL IT FROM THE KICKER COVER. PURCHASE A $20 OBD2 PIGTAIL FROM EBAY AND EXTEND THE WIRES NO MORE THAN 30 INCHES. EXPECT CODES. MOSTLY IDLE CONTROL CODES. EVAP CODES ARE COMMON NO MATTER WHAT YOU DO. PLACE A SPARK PLUG ANY FOULING COLLAR BETWEEN THE DOWNSTREAM O2 SENSOR AND THE CAT/PIPE. THIS WILL ELIMINATE CATALYST CODES.

[@TyceFerwerda]

Hey Mick. Tyce here, we have chatted a few times. Any still wrapping my brain around the DIY harness process and I am going to make a recommendation/suggestion/request. It would be better for a DIYer to be able to speed up or slow down the video instead of you going fast mode...There is so much detail that is lost...as well as the ability to go back to a very specific spot in the video helps a lot. I am speaking from experience watching over and over your 95-98 DIY harness series...These are greatly appreciated!!!

[@Busaru]

+Tyce Ferwerda Thanks Tyce, I'm afraid an 8 hour video would be a bit dull though ;) I get what you're saying, and I've made an entire series on how to do the harnesses step by step, you may want to check that out then use the specific year videos as a sort of reminder. Check the playlists that I have, I think you'll dig the step by step. Cheers!

[@TyceFerwerda]

Thanks, ya I get that. I guess what i mean is since your doing it anyway, just like the series you did, you could do that same approach. I have watched your video series probably 10 times each and still trying to wrap my brain around what gets cut and not. The main thing I think at this point is the wire harness junctions/splits or whatever they are called that just need to be hacked off is not clear. Ive seen in your vids all those sections but I havent seen a vid that spells it out...Hope this makes sense

[@Busaru]

+Tyce Ferwerda It would be a heck of a lot of work building a video series showing each step for every year and model and engine type for the conversion, that's why I created the generic series which you can apply to most harnesses. Basically you cut everything off that isn't detailed closely in all of the videos. I hope that helps you.

[@junybrown]

Hi Busaru, we already did a swap with a 2003 Subaru Legacy engine in Type 1 Beetle. This Beetle/Subaru has a throttle cable. Now we're placing a 2.0 liter Outback engine in a Ruska VW buggy, without a throttle cable. We just got the EJ20 engine, but we can''t find its harness and ECU. Where can we obtain the harness and ECU? The ebay sellers keep asking for the Outback's part number match, but we don't have that info.

[@fisheyemediakenya6790]

great work. could you please post the two sockets that coonect the engine harness to the ecu with their color codes ?# sg5 turbo

[@michaelswanson1471]

Mick, I am currently doing a converstion on a '91 Caravelle Syncro. The donor car is a '02 Outback. There is one plug that I don't know what to do with. In this video it was blue, about 1 inch wide, and connected to both the OBD II and the ECU (?). Can I just cut it loose and toss it? What is it used for. Thank you.

[@Busaru]

+Michael Swanson It should just fall out of the harness. I kept it in until it naturally fell out.

[@ringo7745]

Hi Busaru, Great videos and very informative. I ordered an 03 2.5l jdm harness and ecu and what I got was labeled 06-09 without the ECU. I do not have the engine yet. So my questions are with matching the ecu to the harness, If it fits the harness and is the correct year will it work? and what is the the time line fitment of an 06-09 harness to an engine so that the connectors and ecu will work. does the dash harness have to match the engine harness exactly or can you make it work if you were to do the harness? or should I just scrap this harness and find a complete doner. Thanks a lot!

[@justmakingit7491]

Hello hope your still on here I am looking at doing the same thing but what did you do about the ignition key switch I was under the impression they hade to be programmed

[@rickrossmechanic65]

Hey mick I have a 02 wrx turbo putting it in my 74 ghia, is this the same I would go by as well

[@junybrown]

Hi, We have the 4B computer, but we don't have the harness for our Legacy 2003. We're doing a conversion to VW. It's discontinued, how can we get one? Can you make the harness for us?

[@1cbread]

Any video on how to make wire loom tester. You make it look easy

[@Busaru]

Well, really the best way to bench test is to supply grounding, 12v+ constant, and ignition power. I made a video on testing in my wiring harness video series - check it out.

[@abefrohman1759]

Are you going to make any more Bugaru videos?

[@Busaru]

+abe frohman Absolutely, I can't wait to get to my personal projects!

[@subarulive6786]

2003 Subaru baja I did ej20 swap but there’s no diagram to show my pin out out from auto to manual

[@barrymcmahon469]

Any info on the 2005 model Legacy loom with drive by wire throttle, any pin out charts? 66 Karmann Ghia with 05 ej20 conversion, once I get past the wiring! Thanks.

[@Busaru]

+barry mcmahon You can find that info in the factory service manual - I have links to them on my website - Busaru.com

[@stefaniealbaladejo4535]

I have wiring for subaru legacy 2.5 year 2001 looking to put it on VW bus 1973 along with motor. Dont know how to do it. where are you located_ do you happen to do the wiring and charge a fee or have one for sale. watch your videos

[@yasmanialarcon6558]

Tienes diagrama de subaru ej15 impreza 2002 de 4 conectores

[@braschilester]

Hello friend, great video of branch, I had a problem with an error P0500 is a legacy gt turbo 2004, I was moving cables from the ecu and the error went away then I moved more things and the error returned, help me.

[@miguelramirez8005]

Are u still doing the wiring I would like to get a price

[@evo6swap]

Do you have a fb page

[@josemontecinos8689]

legacy is the same is outback?thanks

[@rochs_frc]

bro, para subaru 2004 wrx ?

[@blainewalters433]

I'm building a 1968 vw beetle that i'm putting the 2004 subaru impreza motor in it. Any advice on what to keep and what I can cut from the harness?

[@Busaru]

There might be some slight differences from the above video but it’ll be very similar. Just get an ECU pinout and make sure the important connectors are accounted for.

[@blainewalters433]

Iv got the inter harness I'm just having a hard time finding out what to cut so it's not such a mess

[@rochs_frc]

exelente explicacion man

[@albertellis3882]

Are you willing to do a Subaru 2.5 l outback for a sand rail harnass?

[@Busaru]

Sure thing, you can see more here: www.busaru.com/busaruparts/harnessconversion

[@duttyfarm]

I have a 1992 legacy ignition module that I'm putting in my 72 beetle. I am using a microsquirt computer. My ignition module has 5 wires but I can't find a wiring diagram. YELLOW/GREEN GREEN/WHITE. BLACK. YELLOW/RED. BLUE. RED/BLUE. can you tell me how to connect it

[@Busaru]

+Clem Punter it's a 2 channel setup as wasted spark - you'll want to find a diagram. There should be a link on my website under services/resources. Good luck.

[@coolclub4056]

You are crazy my friend

[@Busaru]

+Cool Club Ha! Wires.

[@blakeerdmann]

How much do you normally charge if I send you a full harness? I'm looking to do this swap in my 65 bug

[@rodrigoalvarezgallardo]

ESPECTACULAR TRABAJO. UNA PENA QUE SEA A VELOCIDAD RAPIDA....

[@mfeijo]

Hi reached out to you on Facebook, inquiring about a harness. Thanks.