Options for a Failing Honda Insight IMA Battery

My Honda Insight hybrid is a 2002 model and has already had its battery pack replaced in 2008. Well, in its 13th year (7 years on the new pack), the pack started reporting degradation of the battery requiring some decisions. Considering the value of a car with 165,000 miles and 13 years on it, replacing the pack (even with a refurbished/reconditioned battery) would constitute over 50% of the value of the vehicle, so it’s not a good idea at this point IMHO.

That leaves two options, but if you found this article then I need you to learn from my mistakes:

The Honda Insight, at its core, is a 3-cylinder 67-hp engine and can function without the battery with the loss of auto-stop, regenerative braking, and some MPG. However, depending on when your pack was made, the decision above will be made for you. To explain, I’ll briefly tell you my experience and logic.

My Big Oops

The big concern, with the failing battery pack (ODB codes P1447 and P1449), is that it will not be able to transfer power to the 12v battery under the hood (it acts like an alternator with its DC-to-DC converter) and eventually you will be stranded and unable to start the car. When you Google around, you eventually find the article linked above and some forum conversations about needing to bypass the hybrid battery to make this work.

So that’s what I did. Some sockets, Torx T30 bit, and about an hour and I could easily disable the hybrid battery pack and unplug the Battery Control Module (BCM). However, when I started the car up again, it had a very difficult time starting. I immediately believed it was my small under-the-hood battery and went to my local auto parts store for a free test. The battery was good, but needed a recharge. So, I went for a drive on the highway for an hour, at 2500 RPMs. One important weird behaviour happened: Exceeding 4000 RPM trigged the battery and brake lights to come on, but dropping below 3k for about 1 minute would make the lights go out again. This should have been my first clue.

When I tested the battery again, it had improved, but not enough, and it would no longer start on its own. I had to push-start it (I drive a manual transmission) to get going again. Shortening the story, it was time for a multimeter and some testing and the end result was a loss of charging when idle, and a gain at higher RPMs, but a complete inability to start the car. After speaking with my Honda Dealership rep and a 3rd party hybrid specialist, we had come to a few conclusions:

  • Some Honda Insights will continue to work for a long time (lights on/off, charge/assist working and not) without bypassing the hybrid battery
  • It’s no longer recommended to do the bypass because it may or may not work

Based on my research, the reason it may or may not work is because the trick is necessary for original IMA systems. However, remember, my pack was replaced in 2008 (there was no sticker on the BCM when I opened things up; my second clue). Honda updated the BCM with the pack, and thus they made the trick unnecessary. So, the decision is made for you: if you have an original pack, the bypass will be necessary. If it’s been replaced (I’m guessing that covers 99% of Honda Insights due to the 10 year warranty), then it’s not necessary.

Of course, if you need to pass an emissions test, you’ll need a replacement battery pack, because you’ll have that Check Engine Light. :( For me, I’ll be retiring my Insight 3 months shy of its 15th birthday. It was a good run.

Update: June 2016

It’s hard to say why, but I went into the dealership to have any error codes cleared and suddenly everything that was working fine (no large battery) went to hell. Long story short, I was dead in the water. The vehicle would no longer function disconnected from the system as a DC-DC converter and thus I had to either sell a dead car or replace the pack. I replaced the pack for ~$2500 (not at the dealership). It’s running great now, back with a battery, now that its life has been extended. It seems 15 years was just not enough in its heart, so we keep going.

26 thoughts on “Options for a Failing Honda Insight IMA Battery

  1. Ramon Enrile

    I have a 2010 Honda insight with 210k miles . The IMA Been driving it with the IMA light on . So only the regular battery is working . When I tried to drive with the AC on and parked with the AC running the red battery indicator came on . Like it’s not charging but still drives . It may have depleted the regular battery so I installed a new battery . Hoping that would fix the red battery light on . But then it came on again . Is it safe to just ignore and keep driving ?

  2. Jim

    Our 2001 Honda Insight IMA light came on then it just quit. Do you know anyone that would use it? We are in Leakey, Texas northwest of San Antonio. Thank you, Jim Reed 830-232-5096

  3. Derrick

    I have a 2001 insight and replaced the battery over three years ago, because the Portland “place” that sell the 2500 $$$$$$$ told me it was out of warranty; wow! it doesn’t seem like it and everyday I drove it I was wondering if I ever had to do that again. Well, yes, the ima light came on yesterday between Portland and Salem and I got the p1447/p1449 error. I am really angry. I just retired and now i have to deal with this crap again. I’m calling this place today……………

  4. Donald D Broughton

    I have followed instructions to bypass my hybrid battery in my honda insight 2000 and it is working just fine with one nasty little issue. I live in Pima County AZ which requires an emission test (and) you may not have a “check engine” light lit which results in an automatic failure. When my next test comes due in March, I must fix the light or no license. My mechanic can turn off the check engine light but it comes right back on. The engine, of course, passes the emissions test just fine. I need to find someone or a method to turn off the check engine light pertaining to the bypassed battery or will have to just give the car away and I would rather not. The car has 197000 on it and I have replaced under warrenty, one hybrid battery and twice paid $2000+ since then. It does not make financial sense to keep replacing the hybrid battery at that cost per mile. Without the hybrid battery, I am still getting over 50 MPH in town so could drive the car for many miles more so I would love for the check engine light to go away. Any help would be greatly appreciated.

    1. Mario Lurig Post author

      I feel ya, I was in the same position… next emissions text it would fail with the check engine light. No good solution since it’s fixed rules that the emission testing team have to follow.

    2. Christopher Congleton

      Have you already used a grid charger to balance the pack, discharge it and recharge it 3 times in a row? You can buy a grid charger/discharger for $170-$350, install it in a few hours of labor, do the charge/discharge procedure over a 2 day period, and probably be able to pass smog. It’s involved but it’s the Hail Mary you’re looking for. I have a hybrid automotive charger and a cheap one off eBay coupled with a light bulb fixture with bare wires that both have worked for this. Here’s the reconditioning procedure:

    3. Phillip Gonzalez

      There is a guy selling a 2002 insight with 130,000 in the town that I live in. he says that the battery pack and IMA are shot but he is only asking 500 for the car, I was thinking to take a chance. What do you think

      1. Jerry Underwood

        If you don’t do it, I would love to have the car to fix some damage my wife’s insight has suffered over the years.

    4. Ricky Garner

      I just replaced the battery pack in my 2001 insight, and nothing changed. The 12 v battery light and check engine light remain on. 12v is good. Any suggestions?

    5. Alan

      I’ve been driving my 2000 Insight for about the last 6 months with the IMA light on. I have 247K miles. I have no intention of sinking anything more than $200 into this car because it’s just not worth it. I found the same issues as mentioned above . . . if I exceed about 4,000 RPM, the alternator light comes on and it stops charging . . . it usually goes off after a minute or two. So I try not to exceed 4,000 RPM. It’s rather sluggish getting started, so I have to ‘double-clutch’ it, but does fine once I get it up to speed.

      1. G Bains

        yep. My friend’s 2000 insight runs wo ima for a bit now (1 year). i don’t push start it, but it needs a gas pedal pump to start. you can’t have the heater all the way up (3/4 blocks ok) or the AC on for long when idling. Just get a power pack in case you need a jump. I just took a 3000 mile trip with it (driving at night and all). It gets 50 mpg. It’s anemic, but the car kind of is, rather generally. keep the rpms down.

  5. Bill Biederman

    I am driving a 2003 Honda Insight CVT. Having issues in that the rpms are running too high thus impacting the mileage. What should i be looking for to either replace or readjust in order to be able to bring down the rpms? Filters, oxygen sensors or possibly is there a software adjustment that needs to be made. Body is perfect and I would like to keep it running. All advice is welcome.

    1. Byron Reed

      After this long I’d recommend replacing the spool valve, oil pressure sensor, and adjusting the valves. Does wonders.

  6. Darrell Roeters

    I’m looking at a 2000 insight with 32,000 miles. The car hasn’t been used in 7 years, original owner broke his back. It’s red and body is in good shape. He’s asking $2,500 is it worth it?

  7. Mike

    I hope you don’t scrap it in the end as there is a wealth of information to restore the batteries out there, not to mention the fact it is a VERY rare sought after car now. I hope it survives :).

    I am currently in the market for such a vehicle no matter the battery condition if you still have it!

    1. Timothy McCray

      I have one for sale which is actually in pretty good condition the battery is failing though but it is a pretty clean car it has about a hundred and forty two thousand miles on it and because I know that you would probably have to buy a battery I’d be willing to let it go for 2 Grand

  8. Andrea

    My check IMA light turned on in late January as well and I have a 2010 Insight (Only 65K miles). I took it to two dealerships and they basically gave me the same treatment as Alison. Seems to be that Honda doesn’t want to honor their warranty…

  9. Alison

    I have a 2010 insight with 107k miles on it.
    So even though it’s only 6 years old, Honda says it’s out of warranty.
    My Check IMA light has come on and gone off twice within the past year, and it has just come on again yesterday.
    Can I continue to drive it? I’m having trouble getting a straight answer from the dealership, since they keep trying to sell me either a new IMA battery or a new Honda, neither of which I can afford right now.

    Thanks for any help you can give!

  10. Amy Alkon

    Wow – thank you. So, a question: If the “check engine”/IMA lights are on, and if you had a new battery put in by a dealer in Sept. 2014 (in a 2004 Insight), you can just do nothing and still drive the car? (But you will not be able to smog or sell it?)

    1. Ivan Jekel

      Thank you for that assurance. I have a 2000 insight with 326,400 miles and a low battery pack that i do not wish to replace. I get the impression that if i keep driving it it should be ok . i do not need the assist anyway. Are you in a similar position? if so how is it going. Anyone please respond, I do not want to lose my insight!!!!!

      1. Alan

        I also have a 2000, now with 247K miles. Have been driving it for about 6 months without the IMA.
        I’m going to keep driving it until it dies. I have to do some wierd things now to get the A/C to work though.


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