ECU pinout M3 vs M1/M2

Hi all!
I’m (hopefully) going to put a 3SZ into my L701 (Cuore), but I ran into a problem.
To make sure everyone knows what I mean:
SIRION 2 = M3
YRV = M2
SIRION 1 = M1

So, I wanted to use the harness from an M2 or M1, because those are pretty much plug and play in an L7. However, the ECU plugs from the M3 are not the same as the ones from an M2. Therefore, the M2 harness will not fit on the M3 ECU. I made an Excel-sheet to compare all the pinouts from both ECU pinouts (M3 vs M2).

The biggest problem is that the M3 has a lot more pins than the M2. Not all of them are in use, but to give you an example: the M3 has CAN, and 4 ICMB (ion current combustion signal) signals, whereas the M2 has no CAN, and just 1 ICMB signal. There are a few more of these pins, but I think you get the point. I know I can probably use the M2 harness, use the M3 ECU plugs, and make sure all the pins are in the correct place, but I’m worried the engine won’t start, doesn’t run properly, or gives me a dashboard full of Christmas lights. I’ll post a few pictures below to clarify a few things!


YRV ECU pinout



SIRION 2 ECU pinout

Going back to the ICMB signal I was talking about earlier: looking at the M3 pinout, you can see that pins 48 - 51 are all ICMB, while the the M2 has only one ICMB signal (pin 14).

I’ve thought about using the engine-harness from the M3, and the interior-harness from the M2, which makes sense in the first place. However, the engine-harness has to connect to a fusebox, and guess what? The M2 and M3 are not the same :slight_smile:.

I know @Speedpower and @thefiztec have done it before, but I have no idea how they’ve managed to do that with the M3 ECU.

Please let me know if you need more info to help me :smiley:
Thanks!

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this is part of the Excel-sheet I was talking about. Column A shows the pinout numbers, column D shows which M3 pinouts are the same as the M2 pinouts on the left. Green is the interior-harness, orange is the engine-harness

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diagram M2


diagram M3

looking at this, I think it might be possible to use the engine-harness from the M3 and figure something out for the fusebox, but I’m still not sure.

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That’s allot of work you’ve done! I’m going to download these pages if you don’t mind. I’m afraid I can’t help you but I’ll be lingering around.

I don’t mind at all, that’s what the forum is all about :wink:

hi there. FYI i’m not using M3 ECU. i’m using a Storia K3-VE2 ECU. Come with M11 code on it. Basically it has the same ecu pinout with YRV (M2) For engine wiring harness, I’m using back my stock YRV harness.

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May i know what are you planning to do. What i mean is what are the part that you currently have in your L7? Do you already have a YRV/K3 engine swapped before or you are coming from bone stock EJ

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I still have the EJ, and will swap that with the 3SZ. I figured I’d need the 3SZ ECU, because of the larger displacement of the engine (1.5 vs 1.3). It made sense to me that that means the fuel injection is different (needs more fuel) compared to the K3’s

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