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Discussion Starter #1
The past few days the red 12V battery light on my 2000 Insight has gone on intermittently. No IMA or CEL on. When that happens the car starts from the starter motor rather than the IMA and this morning seemed as though it would not turn over. I restarted, the light went off, and 20 miles off to work I went. Upon parking I attempted to restart and, once again, break light came on along with red 12V light, and did not start from Assist.

Lunchtime everything started normally. I went closeby to Autozone, they said there was a bad cell, and I needed a new 12V battery but the battery was fully charged for now. They did not take the battery out of the car for further testing.

1. Could a bad battery cause these intermittent issues or is it likely something else?
2. Autozone suggested a Duralast battery w 500 cranking amps- does this sound right?
3. Can the car power down while driving or will it just not start?

All input appreciated.
Kathie-
 

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Linsight Designer
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A: The DCDC converter directly controls whether the "Charging System Indicator" light is illuminated ("CSI light"). Nothing else can directly turn the CSI light on.

B: If the CSI light is illuminated, then the "Brake System Indicator" light will also ALWAYS illuminate. This is because there is a diode forward-biased from the BSI light to the CSI light.

C: Thus, the DC-DC is illuminating the CSI light for one of the following reasons (inclusive):
C.1: The DCDC is overheating (unlikely)
C.2: The MCM has disabled the DCDC (by pulling GRN/BLK wire low). This will occur when the IMA battery pack is so far gone that the MCM decides to disable the entire IMA system. If this is the case, then disconnecting the BCM connectors (as shown in numerous spots on this website) will temporarily 'solve' the problem. However, this isn't the case, as the MCM would also illuminate the IMA light.
C.3: The MCM misinterprets logic signals due to faulty ground straps. To the DCDC, this is technically the same as C.2, as the MCM will pull the GRN/BLK wire low. Replace ground straps. Note that the IMA light might not illuminate, as the ground reference mismatch could be due to a logic shift seen by the DCDC, but not the MCM (i.e. the MCM could think it was enabling the DCDC, but the DCDC could see the same signal as "disable", as this is a PHY-level hardware issue).
C.4: The car isn't started. Technically, this is the same case as C.2, as the MCM pulls the GRN/BLK wire low until the car has been started.
C.5: The DCDC input voltage range is too low/high (~80-205 volts expected). These conditions occur when the engine RPM is too high/low and the IMA battery health is poor; the battery can't regulate the rectified input voltage.
C.6: The 12 volt output voltage is too low. Note that if the IMA system health is good, AND if the total 12 volt current is less than 75 A, then a dead 12 volt battery WILL NOT cause the CSI light to illuminate. To clarify, if the IMA system is operating to spec, then you can actually completely remove the 12 volt battery from the car once the car is started (even with autostop). C.6 is so because the DCDC completely regulates the output voltage*. If the output voltage sags too low, it's because the DCDC isn't outputting enough current. The ECM can control the DCDC's actual output voltage (either 12.x or 14.x volts, based on engine temperature), but it cannot control anything else. The MCM can only disable the DCDC, and it will do so only as described in C.2, C.3, and/or C.4.

*Note to nerds: the DCDC's worst case closed loop response time is a few hundred microseconds. That means the voltage sag from an applied worst case load step from 0 amps to 75 amps is fully restored in ~1/3000 seconds. In other words, those that claim a battery is required to "smooth" the DC signal should actually probe the 12 volt rail before they challenge my observations. If you want to debate this issue, you'll need to first send me oscilloscope captures refuting my claim. I'll then send you lowpass filter calculations showing why this response time is ultimately irrelevant.

...

With the above in mind, let's look at your questions:

1: Once the car is started, a bad 12 volt battery cannot cause the CSI light to illuminate, UNLESS the battery is defective and sinking more current than the DCDC can provide (75 A, which would quickly cause the battery to overheat). To test for a bad 12 volt battery, disconnect the 12 volt battery after the car has started and the engine is in autostop. Vehicle should remain on (DCDC sources all current). Your 12 volt battery could in fact be defective, but that's not why the CSI light is on.

2: As long as the terminals mate and the battery physically fits in the tray, any 12 volt car battery will work in the insight.

3: I don't completely understand the question, but if the battery light is coming on while you are driving, AND the IMA light doesn't come on, too, then the primary root cause is almost certainly bad ground straps.
...

Recommendations:
1: Replace ground straps.
 

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Discussion Starter #3
location of ground straps for 2000

Anyone know of a document or link listing all the ground straps and where they are located?
 

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Anyone know of a document or link listing all the ground straps and where they are located?
They are located in the google search box in the top left of your screen.

"ground straps" will give you a link to the 4 with pictures
 

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Discussion Starter #5
A: The DCDC converter directly controls whether the "Charging System Indicator" light is illuminated ("CSI light"). Nothing else can directly turn the CSI light on.

B: If the CSI light is illuminated, then the "Brake System Indicator" light will also ALWAYS illuminate. This is because there is a diode forward-biased from the BSI light to the CSI light.

C: Thus, the DC-DC is illuminating the CSI light for one of the following reasons (inclusive):
C.1: The DCDC is overheating (unlikely)
C.2: The MCM has disabled the DCDC (by pulling GRN/BLK wire low). This will occur when the IMA battery pack is so far gone that the MCM decides to disable the entire IMA system. If this is the case, then disconnecting the BCM connectors (as shown in numerous spots on this website) will temporarily 'solve' the problem. However, this isn't the case, as the MCM would also illuminate the IMA light.
C.3: The MCM misinterprets logic signals due to faulty ground straps. To the DCDC, this is technically the same as C.2, as the MCM will pull the GRN/BLK wire low. Replace ground straps. Note that the IMA light might not illuminate, as the ground reference mismatch could be due to a logic shift seen by the DCDC, but not the MCM (i.e. the MCM could think it was enabling the DCDC, but the DCDC could see the same signal as "disable", as this is a PHY-level hardware issue).
C.4: The car isn't started. Technically, this is the same case as C.2, as the MCM pulls the GRN/BLK wire low until the car has been started.
C.5: The DCDC input voltage range is too low/high (~80-205 volts expected). These conditions occur when the engine RPM is too high/low and the IMA battery health is poor; the battery can't regulate the rectified input voltage.
C.6: The 12 volt output voltage is too low. Note that if the IMA system health is good, AND if the total 12 volt current is less than 75 A, then a dead 12 volt battery WILL NOT cause the CSI light to illuminate. To clarify, if the IMA system is operating to spec, then you can actually completely remove the 12 volt battery from the car once the car is started (even with autostop). C.6 is so because the DCDC completely regulates the output voltage*. If the output voltage sags too low, it's because the DCDC isn't outputting enough current. The ECM can control the DCDC's actual output voltage (either 12.x or 14.x volts, based on engine temperature), but it cannot control anything else. The MCM can only disable the DCDC, and it will do so only as described in C.2, C.3, and/or C.4.

*Note to nerds: the DCDC's worst case closed loop response time is a few hundred microseconds. That means the voltage sag from an applied worst case load step from 0 amps to 75 amps is fully restored in ~1/3000 seconds. In other words, those that claim a battery is required to "smooth" the DC signal should actually probe the 12 volt rail before they challenge my observations. If you want to debate this issue, you'll need to first send me oscilloscope captures refuting my claim. I'll then send you lowpass filter calculations showing why this response time is ultimately irrelevant.

...

With the above in mind, let's look at your questions:

1: Once the car is started, a bad 12 volt battery cannot cause the CSI light to illuminate, UNLESS the battery is defective and sinking more current than the DCDC can provide (75 A, which would quickly cause the battery to overheat). To test for a bad 12 volt battery, disconnect the 12 volt battery after the car has started and the engine is in autostop. Vehicle should remain on (DCDC sources all current). Your 12 volt battery could in fact be defective, but that's not why the CSI light is on.

2: As long as the terminals mate and the battery physically fits in the tray, any 12 volt car battery will work in the insight.

3: I don't completely understand the question, but if the battery light is coming on while you are driving, AND the IMA light doesn't come on, too, then the primary root cause is almost certainly bad ground straps.
...

Recommendations:
1: Replace ground straps.
Anybody have thoughts on my update below? And thanks Mudder for your detailed response.

After Autozone told me I have a bad cell in my 12V everything has been fine and I planned to replace the 12V battery on my day off tomorrow.
But this morning again the CSI battery light (also Brake and ABS light) came on, and the car again started via the starter motor rather than IMA. I drove it and no IMA light came on but the car died while driving. Zilch power, not even warning flashers.

I had it towed to the stealership since the battery is under warranty. I asked them to check the ground straps but they said they will only do a standard diagnosis(extra charge) that's not part of the battery install and they won't honor the warranty without a receipt which I don't have with me. GRRRR!

I will have the battery put in but am back to square one with the ground straps and this intermittent problem. Also I asked the AAA guy to jump start the car and it again was acting fine (no lights) and the hybrid battery showed full charge.

Does this provide more insight (pardon the pun!) as to what is causing this or what to rule out? Are there any users here local to Atlanta that could help me?? I don't have the tools or know how to do this myself.

Kathie-
 

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Linsight Designer
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Did the CSI light remain on while you were driving (before the car died)? If so, I suspect that both the IMA battery AND the 12 volt battery are dead. What probably happened was the IMA system disabled the DCDC converter, forcing the 12 volt battery to take over. If the 12 volt battery was also defective (sounds like it was), then that would explain why not even your flashers worked.

The reason the car acted fine after the AAA guy jumped your car was that the MCM reset, and when powered back up assumed the IMA battery was good... hence the DCDC was on. When you got jumped, did the battery gauge immediately show full charge, or was it blank for a few minutes and then showed full?

...

In summary, I propose that both your 12 volt and IMA batteries are dead. You will need to replace the 12 volt battery, but it will just die again unless you 'fix' the IMA problem, too. The cheapest way to 'fix' the IMA is to unplug the BCM connectors, which will keep the DCDC enabled (and hence the 12 volt battery charged). This will work until the IMA battery gets REALLY screwy, at which point the next cheapest step is to turn the IMA battery switch off and cut the GRN/BLK wire that connects to the DCDC converter; this prevents the MCM from disabling the DCDC. At that point, the IMA battery, MCM, and BCM are just dead weight and you can remove them. Of course, you'll have a check engine light and won't pass inspection.

The next cheapest option is to add a grid charger to rejuvenate the pack. This will work wonders for a while.

The last option is to replace the NiMH IMA battery.
 

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There's a lot of clutter in here:

Your 12V is diagnosed as bad. Unless I missed something, absolutely everything you have described can be caused by a bad 12V battery.

Absolutely nothing can be done from a diagnostic perspective until the 12V battery is replaced. Symptoms have no meaning. It's like saying, "my front tire is flat, but my steering is heavy."

Once the 12V is replaced, you can proceed with diagnostics provided symptoms return.

Please replace your 12V and post the results.
 

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Discussion Starter #8
12V died

Answers to questions-

"Did the CSI light remain on while you were driving (before the car died)?"
Yes, a lot of lights came on"

"When you got jumped, did the battery gauge immediately show full charge, or was it blank for a few minutes and then showed full?"
IT was blank until I revved it in neutral for about 4 minutes and gradually climbed to full charge. This is in line with what it does anytime the 12V is disconnected.

I am getting the battery changed now and will report back.
 

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Don't forget to fix/replace the ground straps also.
 

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Discussion Starter #10
There's a lot of clutter in here:

Your 12V is diagnosed as bad. Unless I missed something, absolutely everything you have described can be caused by a bad 12V battery.

Absolutely nothing can be done from a diagnostic perspective until the 12V battery is replaced. Symptoms have no meaning. It's like saying, "my front tire is flat, but my steering is heavy."

Once the 12V is replaced, you can proceed with diagnostics provided symptoms return.

Please replace your 12V and post the results.
I replaced the 12V and so far no symptoms. The problem only occurred after driving in rain and no rain since if that matter. There are 2 good ground straps and 2 bad ones- one to the transmission and don't know where the other is (but mechanic said the ground straps connect to battery are fine). Mechanic won't even order until he gets confirmation of location and part number from Honda.

I found pictures through threads naming them G1 G2 G3 G4 T4 T5 but could not find description or part number.

Does anyone know what the respective part numbers are?

Is it safe to drive the car- mechanic says ground to transmission is barely hanging on.
 

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You are running around in circles. REPLACE THE DAMN ROUND STRAPS! Especially the one that is "barely hanging on,"

Willie
 

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And there is no need to get them from Honda. Just get a generic one from any parts store. It'll be faster and cheaper. This isn't rocket science.

Sam
 

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Discussion Starter #13
And there is no need to get them from Honda. Just get a generic one from any parts store. It'll be faster and cheaper. This isn't rocket science.

Sam
Sorry guys but I am at the mercy of a mechanic. I'm all for replacing ALL the ground straps but they will only replace the two that are bad and want to make sure they get the right part for the right ground strap. I wish I had the tools and just a LITTLE bit of mechanical knowhow to do this myself but I do not.

If any of you are in the Atlanta area and can help I will pay for your time.

-Kathie
 

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Just tell him that it's the two under the air filter box that cause the trouble. And the negative battery cable. When he sees them he'll understand that they are nothing special. Don't worry about the one by the steering rack. It never causes problems.

Edit: Natalya, can you help her?

Sam
 

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If he can't figure it out, I would find a different mechanic. Nothing special about the cables.

HTH
Willie
 

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Discussion Starter #16
If he can't figure it out, I would find a different mechanic. Nothing special about the cables.

HTH
Willie
With all due respect for the mechanic(actually his parts guy) he simply wants to make sure he is putting the right ground cable into the right location. The ground straps are not the same. Honda says they don't know which one it is. I'm sure somebody here has gotten from Honda. Can someone please help?

The bad ground straps are NOT connected to the battery- one is to the transmission and the other is to a bracket according to mechanic. The two battery ground straps are good.

I would really appreciate the help. These guys have a good reputation and I'd rather not have to go mechanic hopping.
 

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That's the whole point. Nobody gets them from Honda. It's just too easy to go to AutoZone, or any other parts place, get a couple of ground straps, and undo four bolts and bolt them on. Length doesn't matter, as long as they're longer than the old ones. 8-12" should be fine.

I did a search and found this in an old post.

Here's the part numbers for the ground wires. ~$7/each online. Probably a few dollars more at the local dealer.

Cable Assembly, Transmission Ground 32601-S3Y-J00 (this is for manual transmission. Not sure if same part for CVT)
Cable Assembly, Sub-Ground 32610-S3Y-000


Sam
 

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Hey redracer, I live north of Atlanta and I work inside the perimeter. I can install new ground straps for you, I had to do it on my first Insight.

I'll send you a PM maybe we can meet up this week?
Redracer: An awesome offer from a highly respected member here on IC. Natalya will steer you straight.

Another reason why this forum is the best :)
 
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