Hi,

First of all I have been reading this forum for a while as guest and I've found it to be really informative. Thanks for that.

I've been using a 2011 HCHII for four months now and I've been loving it. The millage of the car is just over 31000 kilometers.
However just a couple of days ago the IMA warning indicator popped up just when I entered a freeway after being stuck in urban traffic for a while.
The check engine light did not come on.

While I was cruising the highway with the light on, the assist and charging worked with acceleration/braking and I didnt notice a loss of MPG as well. In the freeway exit (15 mins since the IMA indicator came on), I stopped the engine and restarted and the light automatically went away.

Then I drove for about 100km in the reset of the journey and the indicator did not come on after that.

Today morning I did a power reset and drove it for a while. The battery operated as usual and it was assisting during acceleration.

Maybe it's just me but I remember IMA system used to give 2-3 bars of assist when cruising at a steady speed with the foot very lightly on the accelerator, at around 50-60kmph speed. I noticed that this type of assist was not coming anymore after the IMA light came on and went away.

My questions :
1. When the IMA light comes on, does the IMA system get switched to some sort of different mode? Like reduced assists? Assists are working as usual when accelerating, Auto Stop works as normal, it's just that I feel assists are lacking during a cruise. And maybe a one-two squares on the mpg meter is reduced too. Maybe its just me.
If it does indeed get switched to some reduced mode, how do i reset it?

2. Sometimes when the battery is 4-6 bars full, I still see a one bar of CHRG while cruising. Is this normal behavior? I checked my 12v battery and it's giving the correct voltages. 12v idle and 14.2 hot.

I would be grateful if you could provide any info on these. Thanks in advance.

 

I'm no expert, believe me, but I did just have the battery replaced on my 2009 HCH. Mine was experiencing a great number of IMA problems before my light finally came on. When the light did come on, I made an appointment with Honda for the next day. Despite the fact that the IMA light was no longer illuminated, the code was still in the computer, and Honda replaced the battery.

Just my two cents, but if you have the time (it doesn't take long for Honda to read the codes and make a decision) I'd just get it checked out. Your vehicle is under warranty, so if you can get the issue (which doesn't seem like an issue yet) addressed early, you'll have less hassle later.

Good luck!

 

Your 12V battery should be at 12.8V after sitting for a few hours or overnight. At 12.8V, a car battery is at 100% charge. At 12.0V, a car battery is only at 35% charge, and at 11.5V, a car battery is -DEAD- and wouldn't be able to turn a starter.

The only way to really know, however is with a resistive or capacitive load test. You can get this done at auto parts store or you can buy the tools to do it yourself

The 14.2V during run sounds correct. So your charging system is good.

 

Thanks for the info.
Unfortunately my vehicle is not under warranty. I'm from Sri lanka and here the local Honda agents or dealers do not support the HCH. I personally imported mine (like many others around here).
When the IMA light came on yours, did it come with the check engine light? And what other symptoms came with it? Like low PG or frequent re-calibrations?

So far IMA light has not shown up for me after I reset power this weekend. And the car actually did around 50MPG on a long distance trip just after that. It seems to do ~40 on city MPG was well.

Sorry my bad. As I remember it showed ~12.5V with engine off. But I checked this after driving to a local shop - not after idling overnight. I checked using the shops multimeter. Pardon my lack of knowledge, but is that different from a "resistive or capacitive load test"?

 

That sounds better.. and the voltage thing varies with temperature. (the voltages I mentioned were at room temp).

No a resistive tester is more than a voltmeter, but does have a voltmeter display. You are checking the battery voltage while a big resistor is connected. (it heats up from loading the battery). The capacitive tester is a hand-held with large alligator clips that runs a series of tests. You can search for SOLAR BA7 on Amazon to see one.

 

To update my own thread, it was as I feared. The IMA battery was dying and the usable capacity had dropped to 24%.
Luckily, I was able to replace mine under warranty through my importer. The new battery has the code CA3. It's great so far and SoC almost never drops below 4 bars even in heavy traffic. Assists and charging work as intended.

Anything I should know driving with a new battery?

Thanks to everyone who answered.

 

nice to read that,,,, my battery was replaced too! I want to know the same ,,new battery seems to have a breaking period too.... Its working better now,,, 52.2 mpg in mostly trafic drive!colder wheather 49mpg, once I enter to freeway highway,mileage goes higher than 58mpg... Im still confused if I keep the car or resale cause is nice and grat FE, or if I install an amp and focal speakers I have