Honds Civic Gen 8 2006-12 faulty ECU, MCU and immobiliser solution what you need to swap. 

That’s great, I am glad you got sorted. That fuse box is a right pain to take out alright. But like you say, this is the only way to do it. In my case the ECU got fried when an expert shorted a connector. The choice was to scrap the car or try and figure this out. At £35 you did well, mine cost around £80 but it’s still worth it.

​@@Yoke.​Such a great video, thanks for all the precious informations. My current setup is a Civic EG Body with K24Z7 engine, it's equipped with original relay boxes micu//harnesses ECU and car key from CIVIC SI 9th (the actual car i have taken the engine from). Due to project needs I'd like to install an aftermarket ECU like Haltech or AEM instead of the original civic SI ecu, but i know for sure these kind of ECU's don't manage the immo system. From your experience, if the ECU is aftermarket can the immobilizer be triggered directly by the micu/car switch alone? I really hope to turn on the engine with aftermarket ECU

I haven’t had to ever replace it, but I suspect it’s not a stand alone relay. Most likely integrated into the fuse box. And not a stand alone part. That’s just a guess so don’t take it as gospel

It should because your replacing everything, there is no coding involved as all parts come from the same doner.

Yeah this is a European model 5 door model, build Swindon, UK. In this model the antenna, the ecu, and the MCU are all chipped to the key, so you can’t just swap one. I’m in Ireland so it never gets too hot. I looked at the wiring diagram and the immobiliser is integrated, there is no stand alone unit you can replace. You need to swap the whole lot. I’m surprised you were able to replace just the pickup antenna, I tested that at the time and it was it wouldn’t work if it wasn’t matched to the complete the set. Hope this helps, you have a very unusual problem.

@@Yoke. well I didn't replace the antenna myself, it was done by an auto electrician and they had to reprogram it (something) with my key. But the issue remained. Either I got another antenna with the same issue which is unlikely or another part related to it causes the issue. I assumed there is some sort of immobilizer control unit part as well (chatgpt lied to me I guess), but if everything related to the immobilizer in these hatchbacks is the antenna, fuse box (MCU) and ECU, then it has to be the fuse box. If ECU is located under the hood, the only part related to it which remains in the inside of the car is the fuse box. In that case I will order a used fuse box and replace it.

@@BruchoSindicate Buy the full set and swap it out, it’s just plug and play. I got mine on eBay, it was cheap. The MCU is a nightmare to get to, might be easier to pull the driver seat out and lie flat on the floor. You will need a key with that set too and just swap the chip with your key. The pickup antenna can also be swapped without taking the steering wheel off but it’s a bit tricky to get to, I did it so it can be done. If you look at the wiring diagram for the car there is nothing else associated with the immobiliser

@@Yoke. Since I've already ordered and received the entire fuse box (under the dash) I will replace it alone at this point. Sadly the seller didn't have immobilizer and ECU from the same car as well. So I will try my luck with the fuse box alone. I wonder if ignition assembly itself has some electronics which could lead to faulty immobilizer signal when warm. Hopefully not. Logically if we have 3 main parts which could be the issue - ECU, MCU and imob. antenna it seems like the fuse box (MCU) is the only remaining suspect. I will try my luck and let you know if that worked. Hopefully it's not some wire or connector, that would be a hell to troubleshoot. This issue has already been insanely annoying.

@@BruchoSindicate ignition is just a switch, there is no electronics in it. It’s just simple on, off. See how you get on, it’s a tricky one to swap out, loosen what you can, you will also need long nose pliers to pull the connectors and long screw drivers to push the tabs. I suggest wear gloves as there is lots of metal edges, you will cut yourself. Good luck. On a side note, I remember years ago I had a Honda Beat, if you drove it for a long time, turned it off. It sometime wouldn’t start from hot. It turned out the the fuel pump relay was getting too hot, engine was near it. The solder would melt a little and you would get dry joints, I re-soldered it and it never game me trouble again. Could be something silly like that. Where do you live that it gets this hot?

You have to swap all the parts, and they all have to come from the same car. The ring, mcu, ecu and key are all coded

The car had a fried ecu, someone put a positive supply on the wrong connector. The reason I had to swap the ecm, was because it’s all coded to the same key. So you need to swap the lot

Eco is under the bonnet next to the battery and fuse board. The MCU is behind the fuse board at the foot well, and then you need to swap the ring around the ignition. You need all 3 matched to a key, to get this done. Good luck

@@Yoke. mines a 2007 and I've found out that's in behind the Glove Compartment. Hope this helps other viewers.

@@Ash-T-Haqq-Vlogs ah I forgot to ask that very important question, what model was it. My bad, I will update the description. Mine was the 5 door spaceship model, yours is the 4 door I suspect. Thanks for pointing that out

Just a note for viewers. On the 2007 onwards the ECU is behind the glove box. Easy to get to. MICU however as explained by YOKE , is an absolute nightmare to get to.

No I didn’t do any flashing, I bought a complete matched set so I wouldn’t have to do that. All has to be from the same vehicle and then it’s just bolt off, bolt on

@@Yoke. That’s good to hear , I was worry I have to flash it. So I’m assuming everything works great even the key imobilzer with the new ecu…

@@gfhjhvjgfvkjvv3666 yeah it will work for you but you need to swap all the components and the chip in the key as they are all coded even the immobiliser ring around the steering wheel. I found this all on eBay but it’s needs to all be from the same car, you need ECU, MCU (fancy fuse box), key, immobiliser ring, and ignition. Swap them and off you go. Only thing is I knew what caused the issue in my car, so whatever issue you have had to be sorted otherwise you could blow the new one too

@@Yoke. Got it , thks 👍

@@gfhjhvjgfvkjvv3666 good luck

I had a similar issue show up on my 2008 Honda civic Si after a lack of a chassis ground either threw my car into security mode or fried the ECU. The car will start every other ignition cycle but will immediately die after starting. The only cluster lights that come on are the red ring around the tachometer and no door locks, window switches, or sunroof controls are operable within the car unless voltage is applied through a third party power source directly to the unit. I’ve pulled the driver door lock cylinder, ignition cylinder, and ECU and plan to replace the BCM as well for the window/sunroof switches. The power locks still function with the key fob however, which has me stumped. Fried ecu? And what do you recommend I swap out to get it back to functioning as it did before?

@@michaelsapp6675 that’s a good one, I suppose to test the ecu you need specialist equipment to really know what part of the circuit failed. Since your like me doing this at home, swapping one part of this is not really an option as immobiliser will stop the car. The ecu, bcm, key and immobiliser ring are are coded to each other. They only problem in your case is that you don’t know the cause, so you swap it out and it get fried again. You would really need to find the fault first or what happened just before the damage, were you at anything before hand. What caused the damage in this civic was an earth applied to the wrong pin on the air conditioning unit (not by me). Pull up the circuit diagram but everything goes through the bcm and if you swap that you need to swap the rest as you have no way of coding the new bcm.