Help!! Inverter/Motor Control Unit 2012

Mitsubishi i-MiEV Forum

Help Support Mitsubishi i-MiEV Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.


New member
Feb 4, 2022
So one day my 2012 went into turtle mode when I was crossing a bridge I had to coast over to the side where it dies. I waited for about 10 min then it would come back to life and I was able to crawl home. Our dealer has NO idea how to do anything on this car so they called in and got some support - so they say. The said we needed a new brain for it. Ok so I paid the bucks and had it done. Then kept on doing the same thing. Then was on a ferry and it would not go into ready mode. After 16 hours on the ferry and having it towed off they said it was actually the OBC ok so had that changed out as well. 2 weeks later go to leave for work - again no start no ready mode. Now they say its the Inveter/MCU and they say it will be almost $10000 for the part and labor - which I already had $12,000 into this 10 year old car. They gave me the part numbers but I cant find a matching one ANYWHERE - I have found 13 different 2012 IMievs all over the world from Europe to Japan to the USA but NONE match the part number the dealership - who still says they know nothing about these cars and cant tell me if these different inverters will work or not or where I can find a matching car to mine that would have a used inverter to replace it. It has been sitting rotting away for 4 months now at the dealer - they only reason it went back to them is they told me they were going to replace the traction battery that was under warranty but once they got it they changed their mind and wont do it and want to do the inverter. Also paying full insurance for it to sit on their lot. I have little left to spend on this and really need my car back as I am disabled. I have no place to store it and parting it out is not an option nor is junking it with all my money tied up in it. If anyone has any ideas or any thoughts I would BE SOOOOOOO appreciative!! Thanks!!
blackcat604, welcome to the forum and sure wish you had touched base here when you first experienced the problem and before you spent all that money!

Yours is about the worst i-MiEV horror story I've heard of and certainly the most expensive. Paying for a clueless dealer to be hunting-and-pecking trying to solve your problem is outrageous, IMO.

First, we need some information -

1. What is the year and model of your i-MiEV? Do you have CHAdeMO (dc fast charging)?
2. How many miles on it?
3. Does the car charge normally? When fully charged, does the fuel gauge go all the way up to 16 bars? What is a typical Range Remaining (RR) reading you get?
4. When it went into turtle, what was the battery level indicator and what was the Range Remaining reading? Air temperature at the time?
5. Did the dealer perform a battery capacity test and what is that number (in Ampere-Hours)? Were the cells all balanced?
6. What, specifically, is the "new brain" unit that they first replaced?
7. When was the 12v battery last replaced and has it tested good?

If they said it was the OBC and replaced it they should not have charged you for it as it is covered by warranty (10 years) in the USA.

I would not give any more money to the dealer and demand for them to give me back the money already spent as they did not fix the issue.

Some points of reference -

a) The car typically goes into 'turtle' when it detects excessive voltage sag in one or more of the cells inside the main battery pack. Mitsubishi has been pushing back on battery replacement under warranty (yours must be awfully close to the 10-year warranty expiration) and will only do so if the car fails to charge to the full 16 bars.

b) Failure of the car to start is usually traced back to a weak or defective 12v battery, especially if the car was sitting unused for a week or more.

BTW, it's always nice to know where in the world someone is located, as we occasionally find other i-MiEV owners close to us who might be able to help. You might consider updating your profile (which will show your location by your username whenever you post), the procedure described here:

I'm sure others will have additional questions for you as we try to assess what's wrong and before you spend any more money.