'03 MT with P1447 and P1420

[deprior]

Long time off-and-on lurker, first time poster here.

I have an '03 MT with just under 250k miles. Yesterday on the way to work, the IMA light came on. I took it to Autozone to have the codes read and came back with P1447 and P1420. Since then I've already experienced a few positive recals.

The battery pack was replaced at a Honda dealership in Sept. '06 at 147k miles by the previous owner (I purchased the car at 215k miles), so this one has a little over 100k miles on it. I have the paperwork from the replacement. Is there typically any sort of warranty coverage on replacement packs, or am I out of luck there?

Searching forums for the P1420 error, I found this thread, but in my case, there's no check engine light, just the error code that I happened to discover with the P1447. The check engine light comes on when I start the car, so the light itself is working. Does this mean I have a different problem?

[Eli]

The P1420 in your case must be an old code, I wouldn't worry about it if the CEL isn't on.

A replacement battery has a small warranty(3 years, 36k miles I believe) if you purchase it out of pocket. A battery replaced under warranty carries no additional warranty, just whatever is left in the original.

My suggestion is do to several consecutive system resets. Pull the 12V negative cable to reset the systems, reattach it and start the car. The car will start the automatic background charge. Soon, your battery will be full.

Shut it off, disconnect the cable again and do the process over again. Do this 3-6 times, or until your battery goes to full within 10 seconds of the background charge starting.

This is essentially force charging your pack as much as possible. It will give you a bit of extra life, but the ultimate solution other than a new battery is a grid charger.

If you elect to go the new battery route, look into the BetterBattery.

[gilbertguy]

One of the guys on the forum that goes by Varak has gotten about a dozen of these codes over the last 25,000 miles. He would reset as Eli suggested and be able to go 1-2thousand more miles and it would pop up again. He just installed a new Mike D grid charger and seems to have brought his IMA battery back to life.

[Varak]

Just to clarify on the reset procedure, you need to disconnect the negative battery cable for about 30 seconds before reattaching it. That will make sure that the computer 'forgets' the code and the status of the battery. (side note, this will erase all your radio presets).

Once you reattach it, start the car and it will start a 4-bar charge to test the battery. Hold the engine at ~2500-3000RPM until the 4-bars disappear. When that happens, you will see your battery gauge tick slowly up to full.

Repeat several times, as Eli said.

You also want to pull the EPS fuse before doing this procedure to prevent an unrelated engine code being set. It is Fuse #15 in the under-hood fuse box (40A fuse in the middle row towards front of car).

As gilbertguy said, I had the same problem and was able to continue driving for months by doing this procedure several times whenever the P1447 code would reappear. Some times it was a few hundred miles, sometimes it was a few thousand before it appeared again.

Long term solution is a grid charger or a new/reconditioned battery pack, but this should buy you some time to decide what you want to do.

Good luck.

[Eli]

Good points Varak. I guess I usually assume that people's batteries are fairly degraded. It won't be necessary to hold the engine at 2500-3000RPM unless the battery will accept 4 or more bars of charge before the positive recal.

Another thought.. With a severely degraded pack, this may be undesirable overall. I understand that it worked for you, which is a good sign overall. I suspect that your battery is right on the "edge" though.

What causes the positive recalibration is high voltage. A degraded pack spikes higher in voltage under any given charge amperage rate. It would be best to keep the charge amperage as low as possible to extend the input before the positive recal. The background charge at idle will be ~6A, but revving to 2500-3000RPM will increase it to 8-12A. You have the grid charger now, but this would be interesting to test.

Another thing to be aware of is that the IMA light comes on during the charge cycle after a negative recalibration. Avoid the negative recalibration and you can avoid the IMA light. This means being observant of your battery pack to note when the negative recal happens, and then driving as gently as possible to avoid this point. Installing a Calpod clutch switch would probably help in this area.

[gilbertguy]

I got two 1447 codes over about a 3 month period, pulled the 12V neg cable as suggested above and light would go out but when that IMA light came on that 3rd time it was the dreaded 1449 code and all IMA functions stopped working. Even if I did a reset (12v cable pull) it would immediately fail to a code 1449, I think it just depends on how degraded your battery is.

[RedJellyBean]

Originally Posted by gilbertguy

I got two 1447 codes over about a 3 month period, pulled the 12V neg cable as suggested above and light would go out but when that IMA light came on that 3rd time it was the dreaded 1449 code and all IMA functions stopped working. Even if I did a reset (12v cable pull) it would immediately fail to a code 1449, I think it just depends on how degraded your battery is.

When I first bought my car 2000 miles ago, it had a P1449 lit up and none of the IMA functions worked. No auto-stop, no assist, no regen. No nothing.
I disconnected the battery and the IMA came to life.
1000 miles after purchase, during a road trip, IMA P1447 came on. IMA functions remained available, but it took more throttle to engage assist than before.
After resetting the battery again, P1447 has been gone since, but is liable to come back any time. However, I have the Calpod switch installed now, and use assist extremely sparingly, and keep the SOC high at all times. So far so good, but there's absolutely no telling how long this "fix" will work - it's just a matter of time until I get more P codes.
I also have P1420. I had P0420 coming on for the longest time, then I did the second O2 sensor spacer mod with the spark plug anti-foulers - then the P0420 has been replaced with P1420. I suppose that now I should buy a set of plug anti-foulers for the third O2 sensor, I wonder if that will durably handle the catcon codes.
I also wonder if a grid charger, and regular use of such, will keep my battery chugging along for a while longer.

[gilbertguy]

Yes a grid charger will at least stop your battery from getting worse and will more then likely help to restore some of the batteries capability.

[deprior]

Thanks for the responses, everyone. I did the reset procedure several times as suggested, and it has made a big difference over the past few days. I know it's only temporary, but I'll enjoy the improved battery performance while it lasts.

A grid charger and/or a Better Battery is definitely in my future, but I'm glad to have bought myself some time.

I'll give the calpod switch a try too. Looks like an easy install and should save some battery life also.