Unfortunately, I don't have the HCH1 service manual, so I can't say. In the case of the HCH2, a lot of testing is, "replace with known good MCM and re-check."\

In this case, the BCM plug check as you've done is the first step. The second is patch the BCM, the third is replace with known good.

Will the car spin the ICE with the IMA motor to start it, or does it crank with the 12V?

The next thing I would try is discharge the pack to 158V per the HA recommendations and very quickly check the tap voltages again. you may have an extremely weak cell that will hold voltage after being charged, but won't hold charge after being loaded.

 

The car does start mostly with the 12v battery I believe. Although I think it started with the IMA motor once, but I can't be 100% since I cant replicate it again.

I'll discharge it to 158 and retest, will have to be tomorrow. I can retest the BCM connector too. See if the voltage is still similar.

 

All this tells you is that the battery chemistry is NiMH and that there are no completely open or completely shorted cells. There is no (or a very close approximation thereof) battery current in this test so internal resistance changes are not apparent,nor are differences in the amount of energy each cell has stored. Consider what the voltmeter would have shown for two single NiMH cells, one a AAA and the other a cell the size of a 12V car battery. That's right, the same voltage. That is just electrochemistry. The difference between the two types of cells will only be apparent once current is flowing out of (or in to) the cells. (Capacitors are often much the same way: one that retains only a tiny fraction of its rated capacity can usually still be charged up to its rated voltage, with the lack of oomph not becoming evident until a load is applied.)

 

Also, P1570 indicates differences in the stick voltages. When my car has had that condition I could clear it by pulling the number 9 fuse for a minute. Check that it is cleared by turning the key to just accessories and IMA light is off. However, as soon as it turned to the start position, and significant current was drawn from the IMA battery, the IMA light and this code returned. Why? Same as you are seeing - no load, no voltage difference,; load applied, large voltage difference appears.

 

ok. So I just did some more testing. Here's what I have. I tested the taps again just now before I put the load on. Whole pack comes out to 160.7-160.8 ish.

Here's the individual taps voltages.

14-6= 16.08
6-13=16.09
13-5=16.12
5-4=16.18
1-7=16.09
7-2=16.06
2-8=16.05
8-3=15.99
3-9=16.05
9-10=16.05


I then tested the same tap voltages with a load applied. I used the simple discharger from HA. 2 bulb setup, and I put 150w Incandescent bulbs in for the load test. While the bulbs were on and applying load, I took the taps again.

Here's how they tested while under load as a whole pack.

14-6=15.83
6-13= 15.77
13-5= 15.78
5-4= 15.89
1-7= 15.76
7-2=15.63
2-8=15.67
8-3=15.58
3-9=15.59
9-10 =15.66

Still haven't found any stick that is needing changed right?

 

More to note. I put everything back together (IPU cover, rear seats etc). Drove the car 6-7 miles or so. Did a couple of errands. Some different things I noticed.

When I start the car, it starts with 3-4 bars of charge, then the IMA light comes on with the check engine light. I also noticed that the car did use the IMA motor to start the car several times for today's drives. But then IMA light comes on very soon thereafter. Never have had any assist shown though. The 12v battery light of course is on. Today when I was driving it, sometimes it would remain on even when above 1500 rpms. I had to turn the car off/on to get the DC to DC converter to work a couple times today. 80% of the time it would charge the 12v battery when above 1500 rpms. But as I mentioned, I noticed it wasn't charging the 12v twice in my several pit stop drive. So I would pull over, turn the car off and back on to make the DC to DC converter work again. I checked the codes when I got home again. I had the following after today's drive.

P0562- Low Voltage? Today was the first time I seen this code. Cleared it and never came back.
P1435- I had this one a week ago, just came back today on my drive. Otherwise I haven't seen it since. Cleared it, and it seems to have stayed gone again now... weird.
P1570- This code has been with the car since I purchased it on 5-19. I have not been able to get it to clear and stay gone.
P1600- This code has been with the car since I purchased it on 5-19. I have not been able to get it to clear and stay gone.
P1601- Intermittent- Sometimes I have this one, sometimes I don't.

 

I am not familiar with that device, are the bulbs in series or in parallel?

Anyway, assuming the former, P=V^2/R -> R=V^2/P => R=(110*110)/150 =~ 80 Ohms. Two in series would be 160 Ohms. Use 160V for the pack gives about a 1A load. That is better than nothing, but it isn't much compared to the (if memory serves) maximum 45A charge and 100A discharge rates. (Those currents may have been for the Insight I.) Anyway, with no load the maximum voltage difference you saw was 0.13V and with a ~1A load it was 0.31V. If we ignore any measurement errors and the initial observed variation and assign all of it to internal resistance changes that is 0.31V/A = 0.31Ohm difference between the best and worst sticks. That isn't a proper analysis of course. Had a 50A load been applied that gives the nonsensical result of a ~15V voltage differential. Just trying to show that it is not generally possible to extrapolate from the low current test to a high current test. What would happen in the high current test would be that the high IR cells would get very hot, very fast, drop out, make a large voltage difference between the sticks, which the control circuitry would see. At that point a code is thrown the control circuitry throttles the boost or charge way the heck back so that the thing doesn't go up in flames. Mike D. described some of this here:

http://99mpg.com/projectcars/underst...otestabattery/

How old is that pack? You may be able to massage an old pack into a state where it will work, sort of, for a year or two, but the only real solution is to replace it. You could replace a stick or two, but then you still have the problem that all the old sticks remaining are near the end of their service life, plus you need to somehow match the replacement stick to them. If this is a hobby, then more power to you, and have fun. However, if you just want the car to work right, replace the pack.

 

My IMA packs never got that bad - I could always get the 12V light to turn off with high RPMs. Pretty sure though that you are still looking at just an IMA pack failure, it is just getting to the point where the car is having a hard time working around it.

 

The next step in the HCH2 manual for the P1570 is to flash the BCM or substitute a known good one.

I would also unplug the connector and inspect all the BCM pins as well as the connector pins to see if there's any corrosion.