electric motor unit warning light is on

My electric motor unit warning light is on. Never saw that before, the car was just at the dealer a week ago (uh oh)! I was wondering if it might have been a transient error code that can be erased by disconnecting start battery for a minute? Thanks for any advise!

Those error lights are thrown from the EV-ECU based upon CAN buss messages--i doubt that disconnecting the negative terminal of the starter battery would clear it.

i have a theory about the use of el cheapo sliding-contact header pins for transmitting the very important high-frequency control signals to drive the gates of high-power switching transistors--it's basically not a good idea and prone to signal loss and failure, but other than that, it's cheap to manufacture...

Hey kiev thanks for the input. I was searching on forum and seems that light is related to the starter battery? The dealer just changed that battery a week ago! The day that light came on I drove the car all day, depleted down to about 3 bars. The light came on as I pulled in the driveway. I charged overnight, the light is out now. I do have a small powered sub hooked to that battery but it never gave trouble before. I pulled the fuse on that sub. When the light came on, I tried starting the car and I think it started ok, if I remember right. I'll try driving it today and see what happens. After charge it's showing 12.65 volts.

boscoe, before you turn the key in the morning, what is your 12v battery voltage reading?

The i-MiEV will work with even a very weak 12v battery, as that battery's primary function is to wake up the car - once the car wakes up the dc-dc converter keeps the 12v battery fully charged. The dc-dc also charges the 12v battery if you are plugged in and charging your traction battery.

Makes no sense for the 12v battery to trigger the light while you are driving. Perhaps something else is going on?

I'd be inclined to put the monkey onto the dealer's back and let them know the problem started after they replaced the 12v battery.

What caused the dealer to replace your 12v battery?

12.65v is the proper no-load voltage for a fully-charged flooded lead-acid 12v battery at room ambient temperature.

It might have a dirty or weak connection to the battery post. I recall someone else posting saying that disconnecting the 12 volt battery with the car READY caused his warning light to come on.

disconnecting the 12 volt battery with the car READY ??? Yikes, that could make a big spark and cause some real electronic damage on a circuit board or at the main contactors in the pack...

Fuel injected ICE cars don't like it either--trying to jump-start or run with the negative terminal disconnected causes ECU damage. If i had a dollar for every one i've repaired, well i'd be a multi-hundredaire...

Hey thanks for the replies everyone, the issue hasn't happened again. my powered sub is still not hooked up so maybe i'll repower it and see what happens. the start battery was replaced because dealer says it threw a fault code. I did drain it dead a couple times. It was old so I thought sure, change it.

HI all, this topic is a bit old, but I wanted to see if anyone with knowledge on this subject could help me. I have a 2014 Mitsubishi IMEV Electric car, the battery was about half full Thur when I last used it, and today I turned it on, and it won't start. I did notice I left one overhead light on. When I turned it on, all the car dashboard lights came on and a buzzing noise happened, never happened before. I plugged it in for awhile but it wasn't even registering that it was plugged in. The electric motor unit warning light kept staying on even when I turned off the car. Also, the windows and windshield wipers would only work super slowly. Any help? Thanks in advance, Nichole

Howdy and welcome, your car is a 2014, so the 12V auxillary battery up front under the hood is likely worn out and needs to be replaced (6 years +old).

Leaving the interior light on may have run it down so low that it can no longer start the car to READY, and can no longer support the relay and contactor sequence that occurs during EVVSE charging of the pack.

Nichole, welcome to the forum.

A short-term fix to get you running again is to simply jumper the 12v battery from any car onto the i-MiEV 12v battery, being careful when attaching the positive leads to not touch any part of the car body. Any automotive jumper cables work and they don't need to be 'heavy duty'. I usually first connect the (+) cable and then the (-). After you 'start' the i-MiEV (i.e., it goes into READY), the i-MiEV's dc-dc converter will power the 12v battery sufficiently to enable you to disconnect the cables and drive the car.

Even though this 'fix' will get you on the road again, I completely agree with kiev that it's time to replace your 12v battery.

If you cannot replace the battery immediately, it would make sense to attach a small 'float' charger onto the battery whenever the car is not being used.

Oh wow, thanks Joe and Kiev, I can't believe I have to replace the battery already! I bought an earlier version just so I wouldn't have to do that, as I thought one replaces e batteries around 8-10 years old. Aren't the batteries super expensive and do I have to go to the dealer for that?

Nichole

Nichole, we are talking about the auxiliary 12v battery and not the i-MiEV main 'traction' battery which is ~360v and very expensive.

The 12v battery you need to replace is BCI Group Size 151R, found on older Mazda Miatas. Some of us have purchased this one (an AGM which is completely maintenance-free), but needs a block of wood placed under it to match the height of the OEM battery, and now costs about $130:
https://www.batterymart.com/c-Mazda-miata-trunk-mount-battery.html

Regardless, if you don't want to go to the trouble of mail-ordering, you can simply go to your local auto parts store and buy a BCI Group Size 151R and maybe they'll even replace it for you - that's what a local i-MiEV owner here did, but paid ~$175. Hey, even AAA might be able to do it, but I'd check the pricing first.

Good luck!

BTW, it's always fun to know where in the world someone is located, as we occasionally find other i-MiEV owners close to us who can be quite helpful. You might consider updating your profile... http://myimiev.com/forum/viewtopic.php?f=13&t=3196

My local Walmart (Pleasanton, CA) surprised me by having a couple of these 151R's sitting a the bottom shelf in the automotive section of the store. I believe it was $115 plus a refundable $12 core charge. This was a big deal for me since all the auto part stores would have to order it (taking up to a week) plus it they were a lot more expensive there.

Thanks all! I'm so glad I found this great community for our little IMEV cars! I updated my profile with LA, CA and would love to know if others around Santa Monica knew of good mechanics for electric cars so I don't have to keep going to the dealership! On hold now with the auto parts store to see if they have the battery and can install it if I can then jump my car and drive it over.

Thanks again,
Nichole