Galant 2002 GTZ ECU Problem?

Hi Im New to the forum and im more than exited to have found a place where everyone loves the same car as i do, now my car has been good ever since i bought it 3 years the other day i parked my car went in the house came back about a hour later and this happened(i will be as descriptive as possible). When i tried to open the car with the remote the car would not unlock or do anything for that matter i then open it with the key on the driver side and the horn started going off like when you brake into the car, care to note that the car has not been doing the horn when you close or open the car doors with the beeper like it normally would so i was surprised to hear that i go into the ignition and tried to turn the car and it wouldnt do anything all the dashboard light would turn on when key was turned all the way to the on position and when taken back to being just in it would beep like when you have the door that bing bing it does when its open and key is in ignition but it was not constant it was like going crazy making noise at all kinds of rates i pop the hood hear a clinking noise on the fuse box and it was the ECU MR563000 which i think is relay i took it off and it stopped then put it back on and everything happened again with the exception that now the doors open with the remote but when the car is closes you try to lock it the door locks wont go all the way locked they stay half way so the car is technically open.

sorry for the wall of text
hope some one can help me my car is everything to me and its a good car i dont want to have to sell it because some stupid thing.
Thanks in Advance.

Try to Start Car And No Key After
https://youtu.be/c2y4D0_9a3A

Relation With Plug But no Start Or Reaction With Key
https://youtu.be/mIYiEjdZIAY

Relation Between Power And OBD Machine
https://youtu.be/Va_UVW87TEY


No Key Symptom battery removal
https://youtu.be/SUJOoyISQ6Q


No Key Different Symptom
https://youtu.be/Kq0KHO1V9Sk

Key Symptom
https://youtu.be/gWl1CaGaKyc


Dash No Key Symptom
https://youtu.be/lIs_fKTEW10

After Removal of Battery No Key
https://youtu.be/jTJlqZvpMDI

Does car the car start?

It sounds like the battery died or is low.

I have to say that yes that was the first thing i tested but all the electrical stuff happening have told me otherwise like the horn going off and the locls acting funny because everything in the car works but it dont start i turn the key to start it and i get nothing but the response of the front ecu relay going bananas with clicking noise even after intake the key off wont stop until i unplug it.

Sounds like it has an aftermarket alarm and your remote is not program to that particular alarm system. Possibly started because of the car battery being low and the alarm reset itself. The alarm is maybe acting as the kill switch and wont let your start it.
Just my 2cents..

thats a pretty accurate guess , although the car remote is factory and it was programmed over 6 months ago previous to having the same one that came with the car 10 years+ ago also the car acts out with the factory key when i open the car and that is something that was not happening so even if i open the car with just the key im not able to turn it on, also the lights going crazy on the dashboard doesnt seem to have a specific pattern or the horn going off and the most important one the Front ECU Relay going off every single time i try to start the engine the only thing that makes it stop is taking the relay out and plugging it again, Battery is Good i tested it, i have a OBD Reader on the way to read if it has any codes since i cant move the car after that if theres no code i have no idea what i will do to a 100% good functioning car acting this way im really sad.

on another note can some one tell me if in fact is the ECM Computer (already changed the Relay) can i buy a computer from another used car as long as its the same year and make or what is the deal care to note i know what the ECM computer but i dont know anything about how it works and i know that some people has talked about getting them programmed and such if anyone knows more about this and wouldnt mind sharing please. Thanks in advance.

Have you had any of the dash or steering electrical connections apart? I can tell you from recent experience that it can be difficult to locate. Just got my electrical issue sorted...I think. 4 days and no dash light/starting issues. Sounds a lot like the issue I was having. It would through the CEL and then go off just before I could get the reader into it. NO codes. It alternated with the Anti Lock light, but no braking issues. I had also taken out the immobilizer and checked all the wires and connectors. No visible issues. Good luck with the search.

Do you mind telling me what the CEL is? Also im still waiting on some one to answer if replacing the ECU computer is a plug and play as long as the new computer came from the same model and car? Or how is it that it works.

I'm not 100% sure, but I've heard that sometimes our cars have issues replacing the ECU only and not the ECU and Immobilizer as a pair from the donor car, and then reprogramming the keys. The existing immobilizer with a different ECU sometimes has issues with the combination. If I remember right, even if you did go the route of your existing immobilizer with a different ECU, you still have to reprogram the keys, which will have to be done at a dealership/locksmith. I have personally not experienced this, but I remember reading about these problems somewhere.

CEL = Check Engine Light

Will Record video of all the Symptoms and upload them to you tube later tonight, thanks to everyone that is trying to help. I am really desperate to get this solved i will call my mechanic tomorrow he is specialized in Mitsu's to see what he said care to note im on a bind because i cannot move my car.

tamim13 thanks for the insight doing research i read something like that although im still trying to find out what the outcome of doing the ECU and Immobilizer combo and if this is the cheapest most secure route.

I do not want to spend more than $1,000 on my car to get it fixed i know my car is about $3,000 by KBB but i cannot afford it but i most definitely dont want to sell my car knowing it has a lot of life in it still...
again thanks to everyone that is helping and keep the info coming i hope to fix this in the next upcoming week with everyone's help.

***UPDATE***
Got a OBD reader even though it dont have a check engine light will run it and see.

Also to the Symptoms i add that even with the headlights turned off the headlights are on when i plug the battery on the car.

*******ADDED VIDEO OF DIFFERENT THINGS I DID TO THE CAR CHECK THEM OUT PLEASE. *******

Please Close This Thread, Car has been fixed Something electrical was causing the car to drain the battery out in matter of minutes. Thanks everyone that helped.

What was causing the drain, if you don't mind me asking?

Headlights and signals stick had broken inside showing no signs apparently the high beams where activating even when the key was out of the ignition kind of like when you are blinking your headlights to notify some one of theirs being off, and it was hard to tell because at the point i noticed the car wasn't starting everything worked but acted crazy and there were no signs of the lights being on took the mechanic 3 hours to figure out what was draining the power out so he had to replace the whole thing. fortunate enough it was a 300$ fix and not thousands.

The exact same thing happened to me, excpet the switch for the turn signals and lights had completly snapped and it would flop around as I drove so I had to hold it all the way to the shop to provent all my lights flashing randomly lol I thought I was the only one who had had this issue.

This almost cost me losing my car i guess ill be more pattient diagnosing my car will start repairing little details and mod later on this experience showed me how much i love my car.