Check engine with IMA

Discussion in 'Honda Hybrids' started by pasadena_commut, Oct 9, 2011.

  1. pasadena_commut

    pasadena_commut Well-Known Member

    Parked the car outside at the Burbank airport Friday morning, came back today (Sunday) at noon. It was fairly warm the last two days, but not scorching. The HCH1 started up normally (not with the starter motor). Got on the highway to go home and noticed that the IMA light was on. A little later I noticed that the check engine light was also on (solid, not blinking). I'm not really sure when they came on because there was a lot of glare and it wasn't easy to see either of them. Anyway, they stayed on for the 30 minute ride home. The car drove normally, with the SOC going up and down like it usually does, and both boost and regen showing up.

    I though maybe the 12V was going, but measured it right after getting home and it was around 12.3V with the motor off, which isn't terrible. Will check it again later.

    Anything else that would tend to make both an IMA and CEL come on at the same time?
  2. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    12.3 volts isn't that good. Is that the norm for your 12 volt?

    In my experience, anything under 12.5 is iffy, 12.6 and up is better.
  3. pasadena_commut

    pasadena_commut Well-Known Member

    Agreed. Went back out a few hours later and it was reading 12.65. That's 100% charge. The first reading was only about 2 minutes after the car was turned off, and the cooling fans were going. They could have pulled it down a bit. Tomorrow morning will check it again, and then load test it with the headlights on. If the battery still looks OK it goes into the dealer.

    It could be a coincidence, but when a car parked for 2 days in the sun suddenly does something odd, it tends to be the battery. Of course, on this car, there are two...
  4. pasadena_commut

    pasadena_commut Well-Known Member

    At 12.2C ambient the battery was initially 12.53V, but after leaving the headlights on for 3 minutes to get the surface charge off, then turning the lights off again, it had dropped to 12.22V. The temperature correction is .022V/C to compare to 20C, so add .1716 and that's 12.39V, which wasn't great, but not horrific either. Took it in to my local mechanic to have him pull the codes and load test the battery. The battery only tested 60%, so that will be replaced. The code was P1600. He's going to reset the computers after changing the battery. Maybe the P1600 will go away, but it won't surprise me if the IMA really is going out. Luckily this is a California car, well under the 10 year/150K limit, so a failed IMA would be covered. Well, covered as much as anything is when dealing with Honda Service (masters of delaying repairs until all warranties have expired.)
  5. pasadena_commut

    pasadena_commut Well-Known Member

    The mechanic reports that with the new battery and computer reset both the CEL and the IMA stayed off when he drove around the block a few times. Here's hoping it stays that way!
  6. pasadena_commut

    pasadena_commut Well-Known Member

    150 miles after the 12V replacement and so far no IMA light or CEL

    I was hoping that the weak 12V battery might also have been the cause of the occasional instances of autostop not working. No such luck, if anything, that is getting worse.
  7. Gairwyn

    Gairwyn think green

    Regarding the autostop not working, maybe the outside air temp sensor is loose.

    See this thread, where we got into talking about the temp sensor, and the link given there to the Insight forum:

    If your problem is intermittent, maybe the sensor is just coming loose. It's worth taking a look at, as well as any of the other suggestions people had in that discussion, like the brake switch.
    Last edited: Oct 25, 2011
  8. pasadena_commut

    pasadena_commut Well-Known Member

  9. pasadena_commut

    pasadena_commut Well-Known Member

    Rats, it came back on at 600 miles after the 12V replacement. As before, both the CEL and IMA lights are on, but the IMA still seems to be working. Oddly enough, on the exact same stretch of highway as last time, going in the same direction, but not quite in the same place. Apparently my car does not like going eastbound on the 134 through Glendale. The car had been on the highway a couple of times in the interim, but this was the first time back on that stretch of road. It was also the first time the car has been on the highway in heavy rain in a while. Probably none of these are variables are important, it was just time for whatever is failing to fail again.

    Have to take it into the dealer so that they can use their magic machines to get the deeper codes out of the IMA.
  10. pasadena_commut

    pasadena_commut Well-Known Member

    The dealer read a code of P1449 = depletion of battery cel. (My manual is at home, so I won't be able to look up anything more until this evening.) The car is still within the 15y/150K mile warranty, so luckily the big battery replacement isn't going to cost me anything. This is most likely the cause of the intermittent auto stop failures too. In the meantime I will be driving it, ignoring the two warning lights, and hoping that the bad part of the battery pack doesn't choose to flame out in the week or so it will take the replacement to get here.

    This car has not had very impressive longevity. The start clutch in the CVT judders (and cannot be burnished or fluid changed back to health, so in theory it needs a CVT replacement) and the big battery must be replaced. Yet the car is still under 106K miles.
  11. Chuck

    Chuck just the messenger

    Actually P1447 is battery degradation - P1449 is battery overheating...that cell will be replaced - not reconditioned.

    Please note: We ( can only repair batteries that are showing P1447 (battery degradation) or P1449 (battery overheat / battery deterioration / battery deviation) errors. P1600 and P1601 errors often accompany these errors. Anything else may be a circuitry problem and not the actual battery and may need to be fixed by a mechanic or dealer. Please contact us for more information on your error(s) or if you are not sure. We'll be more than happy to help you by providing the information that you need to get your car back on the road.​

    At any rate - it's under warranty! :)
  12. pasadena_commut

    pasadena_commut Well-Known Member

    IMA battery replaced under warranty, the CEL and IMA are out, the autostop works reliably again. Nice! I also notice that the battery stays a lot closer to the fully charged end of the spectrum than it used to before. That could be because of better cells, or because of a different firmware version in the replacement unit.

    They didn't charge me anything but the costs shown on the receipt were interesting. Their cost for the battery assembly seems to have been $1783 but they would have charged $2476. Labor charge would have been $143, miscellaneous would have been $107.84, and total would have been $2747.21.
  13. pasadena_commut

    pasadena_commut Well-Known Member

    I forgot to mention, this was at 106K miles - nowhere near the 150K warranty limit. The time limit was closer, that is only 10 years, and it went at 9 (I think they count from manufacturing date).
  14. msirach

    msirach Well-Known Member

    Glad to hear that your repair went well. You should reap a great benefit from the fresh components.
  15. Right Lane Cruiser

    Right Lane Cruiser Penguin of Notagascar

    That's a great outcome! I'm glad it got repaired for you and everything is working properly again. :)

    The warranty is from "in service" date – basically when the first owner took possession.
  16. pasadena_commut

    pasadena_commut Well-Known Member

    Two and half years later and the replacement pack is failing the same way. Hardly surprising because when they "fixed" it the replacement pack was populated with sticks of the same age, not new sticks. The mileage is well under 150K but it is a year or so over 10 years. So from Honda's perspective that battery swap was a perfect repair - it failed again just outside of the longer California warranty!

    Edit: Read the codes with an Elmscan 5 (which just barely fits onto to the OBD2 connector). Just like last time, P1600 and P1449.
    Last edited: Jul 19, 2014
  17. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Assume this was with the latest software update, that was supposed to be easier on the battery?

    Thanks for the update. We've got an '06 with the IMA battery replaced by Honda (after a long, frustrating decline) about 6 months back.
  18. pasadena_commut

    pasadena_commut Well-Known Member

    2003. Software up to date, but I don't think they dumbed down the assist like they did for the later generations of HCH.

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