Electrical Questions: 2007 WRX Donor

[lpmagruder]

Hi all, first post here. First of all I'd like to thank the countless people on this forum that have created detailed build logs, and documented their work so well. It's because of all this amazing content that I've been able to lurk and avoid creating an account here for many months :-)

I've got an older 818s kit that I bought from someone who originally purchased in 2014 or so, it's got the older style fuel tank/firewall (don't think this changes anything wiring-wise but mentioning just in case.) They hadn't started work on it, so this is essentially a new build, most of the car was packaged as they bought it from FFR. Most of my donor parts are from a 2007 WRX, but it was all purchased years ago by the person I bought this kit from, so tracking anything down from that car is probably close to impossible now.

I've got it built up to rolling chassis and am well underway into the wiring. I am using the Subaru harness, de-loomed and dieted to the best of my ability/confidence. I followed several of the excellent threads around here, along with a 2006 (question on this later) full schematic for wire dieting before attempting to cram it into the car.

My questions:

1. I am worried this question is going to turn into a major headache. The donor parts I got, I am not convinced the key/column matches the ECU/immobilizer. The key is a very cheap/generic looking copied key, not an original Subaru key. I have my harness 90% wired up, enough to hook up the battery, turn the key and the gauge cluster lights up. DBW throttle works (sounds a little buzzy though, maybe this deserves a separate thread/question), relays click, etc. But the "Security" light blinks at first then stays on, and its behavior is no different whether or not I have the immobilizer actually plugged in, which is what concerns me. Is there any way for me to definitively tell if my key/immobilizer/ECU match? The engine I purchased is a bit of a mess, and pretty far from being able to try and start it, so I can't just try it yet. Any paths forward if they don't match, or am I doomed to drop $1500 and redo a bunch of wiring for a standalone ECU, or find a matched ECU set online? I've heard Subaru won't generally re-match immobilizers for these kits.


2. I have a full manual for a 2006 WRX I am using to reference wiring. I'm finding some slight discrepancies, but for the most part it's been useful. I found this manual through searching in this forum, it was on someone's personal blog website (forgetting exactly where) but I remember there was only a 2006, not a 2007. Is there a 2007 manual I should grab, or is this good enough?


3. Can the entire secondary air/AC relay fuse box be removed (F129)? This is the one where the large 2-pin connector for the secondary air pump terminates to. It's got some big wires and arranging the wires neatly would be a lot easier if I can cut the big wires back to wherever they terminate. I do not plan to have A/C (already deleted a lot of the A/C stuff that goes up near the dash), and plan to delete with blocker plates the secondary air pump system. I was originally pretty confident that it could be deleted, but when I started tracing wires into the harness, I saw that some wires branched into many other places, and coupled with my uncertainty on my 2006 wiring diagram being 100% correct to my 2007 harness, I wanted to make sure something else wasn't grabbing power from any of the relays or fuses there.


For reference, this is what the car currently looks like, and what the gauge cluster looks like with the key on (security light stays solid, stops blinking after a little bit)

mV6zBVd.jpg

riB2l4u.jpg

[Ajzride]

1. If your security light continues to flash after you try to start the car, you have an immobilizer issue. I know you can't start the car yet, but turning the key to start and then letting it go back to Run should make the light go out and not flash anymore. I'll see if I can make a video tonight of mine so you can watch it. I smoked my ECU and had to buy a new matched kit on eBay to the tune of $350. I wish I had just broke down and bought a standalone ECU, would have been much cleaner and way more benefit.

2. There is definitely a 2007 wiring diagram it would be useful to have, I just don't know where to get it. Maybe a subaru forum?

3. You don't need the secondary fuse box for the engine to run if you remove the emissions equipment. Depending on what other functions of the stock harness you keep or delete you may need it for them.

[Ajzride]

I made a video but it is probably unnecessary.

With Immobilizer Properly working and key in ignition:
Key off: light flashes
Key ACC: light off
Key Run: light off.

Without key (removed and taken inside away from car):
Key off: light flashes
Key ACC: light on
Key Run: light on

I can make that test pretty easy because I have a keyless ignition and the entire factory assembly is up under the dash with the key always inserted.

I would triple check all of your grounds before you sweat out a new ECU. I had a lot of trouble with mine initially, even tried going to an older ECU without the immobilizer, but once I cleaned up and completed all the grounds it started working reliably.

[RPGs818SNA]

I've got the 2007 wiring diagram and will PM you to arrange to get it to you.

Per the 2007 schematic, the secondary box is just 2 fuses for the secondary air pump and secondary air valves, and 2 relays for secondary air pump and A/C. You should be able to delete the entire box, but be careful to only delete the Secondary Air Pump Relay pin 3, YL yellow blue wire up to the first splice. It's relay coil power from the main relay and feeds a bunch of other things. Do the same with the secondary air valve relays.

Good luck with the immobilizer.
RPG

[lpmagruder]

I made a video but it is probably unnecessary.

With Immobilizer Properly working and key in ignition:
Key off: light flashes
Key ACC: light off
Key Run: light off.

Without key (removed and taken inside away from car):
Key off: light flashes
Key ACC: light on
Key Run: light on

I can make that test pretty easy because I have a keyless ignition and the entire factory assembly is up under the dash with the key always inserted.

I would triple check all of your grounds before you sweat out a new ECU. I had a lot of trouble with mine initially, even tried going to an older ECU without the immobilizer, but once I cleaned up and completed all the grounds it started working reliably.

Thank you for doing this. Unfortunately for me, mine matches your "without key" behavior. When I was dieting the harness I was careful to keep all ground lugs intact and never cut past the first splice for anything I removed, and I marked them with bright tape to try and avoid missing them when doing the semi-final stuffing of harness into the tunnel. Right now I have most of them temporarily grounding to the 1/4-20 rivnuts for the shifter, the engine has ground strap in rear at FFR recommended location, and I believe there was one in the front section I have attached with a self tapping screw in a temporary spot. I'll do another sweep and make sure I didn't miss any.

I've got the 2007 wiring diagram and will PM you to arrange to get it to you.

Per the 2007 schematic, the secondary box is just 2 fuses for the secondary air pump and secondary air valves, and 2 relays for secondary air pump and A/C. You should be able to delete the entire box, but be careful to only delete the Secondary Air Pump Relay pin 3, YL yellow blue wire up to the first splice. It's relay coil power from the main relay and feeds a bunch of other things. Do the same with the secondary air valve relays.

Good luck with the immobilizer.
RPG

Thanks! And right, the power wire for the air pump hits another power wire with 2 or 3 other large diameter wires, the other wires go every which way and most hit another mid-harness splice instead of a connector, I'll cut that box out next time I'm working on it, that'll make the main fuse/relay box mount a little smoother.

[blomb11]

I've got the 2007 wiring diagram and will PM you to arrange to get it to you.

Per the 2007 schematic, the secondary box is just 2 fuses for the secondary air pump and secondary air valves, and 2 relays for secondary air pump and A/C. You should be able to delete the entire box, but be careful to only delete the Secondary Air Pump Relay pin 3, YL yellow blue wire up to the first splice. It's relay coil power from the main relay and feeds a bunch of other things. Do the same with the secondary air valve relays.

Good luck with the immobilizer.
RPG

Could I trouble you to send me a copy of the 2007 wiring diagram? I also have a 2007 WRX harness I have dieted, but I used a 06-07 FSM which seemed to line up. It would be good to check my work though as I get closer to installing the wiring harness. I also deleted the air pump, but was hesitant to fully remove the fuse box since it connected to a few other things. Now it will come out though thanks!

[RPGs818SNA]

Could I trouble you to send me a copy of the 2007 wiring diagram? I also have a 2007 WRX harness I have dieted, but I used a 06-07 FSM which seemed to line up. It would be good to check my work though as I get closer to installing the wiring harness. I also deleted the air pump, but was hesitant to fully remove the fuse box since it connected to a few other things. Now it will come out though thanks!

Certainly! Just post or PM an email address and I'll send it right over.
Cheers,
RPG

[lpmagruder]

Update on this for anyone who has the same problem later. I talked to a local Subaru dealership and confirmed the only paths forward were to either get a full matched key/immobilizer/ecu set through somewhat shady 3rd parties, buy an aftermarket ECU like from LinkECU, or to have Subaru make a new key, and I opted for having them make a new key.

They required the physical car there so I towed it to the dealer on a trailer, and for me to have the title of both the donor car and the 818 (the bill of sale thing you get when you buy the kit.) They sold and cut me an original 2007 key and then hooked up to the OBD2 with a laptop and paired it to the ECU. Out the door it was a little over $200 for the new key and programming labor.

Once he was done with the laptop he had me check it, the car fired up immediately and we checked to make sure the security light was staying off.


Just posting because I think a lot of the guidance is that you're SOL if you don't have a matched immobilizer set, but at least my local dealer was willing to re-pair for me and it was by far the cheapest and lowest risk option considering the cost of matched pairs and aftermarket ECUs online. I think the biggest catch is just that you have to show some proof of legal ownership of the donor car.

[Ajzride]

That’s awesom, glad your dealer helped you out. It should not be so hard to get a key made for a 15 year old car. I’ve heard of a dealer that was adamant they would not make one for a kit car, they would require an actual Subaru with title in their bay to make a new key.

[blomb11]

I know your pain. I checked every signal out of the ECU thinking something was wrong, but everything checked out. I got a 2007 WRX matching key, key ignition cylinder, IMM ECM, and ECU from a forum member. Once I swapped over the new to me parts the car fired right up. I even tried having a lock smith come out first to "reprogram" the key. As you mention I also learned from a local Subaru dealership the VIN or key code is burnt into the matching devices so they are all linked together. The dealership was no help to me so luckily someone on here had parts I could buy from them.

The immobilizer is quite a pain! An aftermarket ECU removes this problem but then you may have issues getting it registered in certain states and particularly for me in CA. Glad you got it figured out!