Battery not charging? Easy way to reset IMA control modules
 

I have to tell this story because find it almost unbelievable myself. I went on vacation and left my car (2003 Honda Civic Hybrid) in the driveway for six weeks. I had asked my brother to start it up now and then, but he didn't get to it. The battery was dead. I jumped it and it started but the IMA light was illuminated and the Main battery had no charge and was not charging. I replaced the 12 volt battery with a new one. The car would start but the IMA light remained on and no charging of the Main battery was taking place.
Also, the red battery image was showing up. I had a bad feeling that the Main batteries were toast and so was the car. This car has over 200,000 miles and I wasn't going to invest 3 or 4k on new batteries. I checked all the fuses, tried removing various fuses which people claimed would reset the system, nothing worked. Then I found a post on a forum by a guy in London who had the exact same symptoms. He claimed that he fixed it by driving his car down a quiet road, not driving too fast, say 15 mph, and switching the ignition off for 2 seconds and then back on. I was a little hesitant, knowing that switching off the ignition would kill the engine and then the power steering and brakes may fade out. However, this isn't a problem if you do it quickly. Once you switch the ignition back on the motor starts right back up, and low and behold, IT WORKS. The IMA light went off and the display showed that the car was charging the Main battery. Just like that.

The car is running fine now and the battery has a full charge. I can't believe it either.

My guess is that this technique sends a surge of electricity to the Main battery and kicks starts the charging process. How exactly I don't know, but it does work.

Re: Battery not charging? Easy way to reset IMA control modules
 

I tried this, I have the same symptoms but could not restart the car till it was put in park. Not even in neutral. I swapped batteries between cars and now both are ima lit with the little battery coming on too. Tried the unhook the battery for 15 min and pull the backup fuse out for 60 seconds no joy.

Re: Battery not charging? Easy way to reset IMA control modules
 

Just to be clear, Homey, the method is to be driving 15 to 20 mph in Drive, switch off the ignition for two seconds then back on. Do not put the car in neutral. The car should restart by compression. Is this what you did and the car wouldn't restart? Possibly you were going too slow. It will also work better on a slight downhill.

Re: Battery not charging? Easy way to reset IMA control modules
 

I shall go give it another go cause I need some luck. The kids car is messed up and mine is too. Oops!


Update: found lots of hills, no problem getting the car to restart. Everything reset, after everything came back ima light, check engine light, alternator battery light under 1500 rpm, same as it was. Glad it worked for you, no idea why it wont work for me but will drive to work and hopefully it will simmer down.

Re: Battery not charging? Easy way to reset IMA control modules
 

Homey. You may need a new 12 volt battery. This car will run not well on a weak battery. You can check your old one out at the auto parts store. If it is at all weak, or over four years old, I would suggest getting a new one.

Re: Battery not charging? Easy way to reset IMA control modules
 

I should have followed up, my bad. My problems were a result of swapping battery packs between cars and it appears they were different be it wiring or software updates. Bottom line is they would not work. I swapped them back, grid charged the bad battery and have seen no more errors since.

Re: Battery not charging? Easy way to reset IMA control modules
 

Glad to hear it.

Re: Battery not charging? Easy way to reset IMA control modules
 

It looks like I may be trying this out. I joined this forum because my mom is having the same issue as AndrewXY described. She had left her car over the weekend and when she got back to it the IMA light was on and the main battery had no charge. she was able to start it and drive it to work on the ICM but today it wont start at all.


Was just wondering if you guys could follow up on this fix now that its been a few months.


thanks

Re: Battery not charging? Easy way to reset IMA control modules
 

I did a grid charge to full and let it sit there for 2 hours, put it back in the car and had no issues for 3 months. No recal, no ima light, worked fine. After 90 days I put it back on the grid charger and charged it up again for 4 hours past voltage increase because my son was taking the car 4 hours away for 4 months (college) and I didn't want him to have any issues. Working good!

Re: Battery not charging? Easy way to reset IMA control modules
 

I don't regard AndrewXY's "fix" as valid.

If at all possible, you need to read the error codes before you do anything including disconnecting the 12V battery. Second, you need to check to see if your 12V battery is healthy. If it's more than 2 years old, consider it suspect. If it's not working optimally, replace it. You can jump start it like any other car if you need to drive it to a location where you can get codes read, but if something else is wrong, you may not get any 12V charging, which will be indicated by the red battery light.

If you can establish your 12V is healthy, and the car will start, rev it to 3500 rpm and hold. You should see it start charging after just a few seconds. Hold minimum rpm needed to keep charging until you see 100% SoC on the gauge.

Homey's grid charge/discharge solution may be warranted if the above doesn't fix the issue.

Good luck,

Steve