Long story short, my tuner went to flash a new setting on my ecu. Then he couldn't reconnect the ecu to the car. It's an evo ix stock ecu. I had an issue with this before and it took several times to get it to read. But he Insists the ecu is bad. Has fully charged mini battery, and it won't connect, start, or connect to code reader. How does that sound to you guys? It was working before all that. So I find it hard to believe it is dead now.

 

I've seen this a couple times with cars that have grounding issues. Make sure all are clean and tight.

 

I noticed that with Mini Batteries, they lose charge required by the ECU rather quickly, fully charged one day and sitting over night in the garage and the next day it wont connect unless I hooked up a charger to it.

 

He had the battery charger on it right before the last time he tried. Even when I had my full sized battery it took a different tuner about 30 minutes to get it to connect to the car. He had to start the car, let it run, turn it off, hook up charger and unplugging and replugging plug in ecu each time he tried to finally get it. I told this tuner that and he put a charger on it tried again and condemned the ecu after it still failed. Might just buy a new one.

 

if you have evoscan read the battery voltage from that. evoscan connects with a lower batt voltage for some reason. I think its under 12vdc that ecuflash doesn't connect from what I remember.

 

The car has over 12 volts. It was on the charger during final attempt. But had the same issue before when it had over 12 volts. It just took a while.. It just seems this tuner is more reluctant to put in time and would rather condemn the ecu. I'm just worried about getting another one and it still happening and I just spent $300 for no reason. He mostly deals with Evo 8s and this problem seems to happen more to 9s.

 

Try a different tuner lol. But no seriously I would try a different cable at least before buying an ecu.

 

just because it was on the charger doesn't mean the ecu is SEEING 12 volts lol. Thats I why I suggested to read the batt voltage with evoscan, that way you can confirm, or meter the power pin for the ecu and see if 12 volts is infact going into the ecu. If it is, bad ecu. If it isn't then you have another issue

 

Good call Galant. I didn't think of measuring the voltage at the ecu with a multimeter. If its seeing 12 volts I still would try another cable. I have a IX too and there has been times my 1.3 cable won't read my ecu even with the battery on a charger. My 2.0 openport works every single time though. What cable is your tuner using???

 

Not sure to be honest. But he tested the cable on another car to see and it worked on the other car. So the cables not bad. I found an ecu for $150 so I snagged it. Will see what happens. Worst case they both work and I sell one for $200.

 

I have seen this issue with the grounding side of the 1.3 cable. Best of luck !

 

Bought a new ecu and as I feared neither will connect. He said the cable works on other evos but not mine so once again, the cable works. Any suggestions? I'm gonna suggest he try a full size battery just to connect.

 

You should have bought a new battery. I too had the same problem and evoscan was reading 12v. Bought a new battery and worked every time since. It's the mini battery that seems to cause issues.

 

mini batteries why are ppl using them if trying to clean up engine bay move to truck.. if trying to lower weight go on a diet. Everyone i know that has those mini batteries all tell me the same thing. dont get one.. thanks for this post confirms move to trunk it is. hope you fixed the problem already.. couldnt imagine not driving my evo everday

 

I've been running my small battery kit for the past 5 years with no issues. Car sits in the garage for over a week and it starts right up no issue either. What battery are you guys using?