[Insight to the Hybrid Era]

Hello Insight Central

I am rather stressed out here in rural Mississippi, trying to get my 2004 CVT to charge the 12 volt system.

I replaced the grounding straps that were on the car. BUT, I don't know if the previous owner forgot to put one of the grounding straps back. I honestly don't know if I am just missing a grounding strap.

Another fellow told me that a high voltage contactor was not working. And then someone else told me that it is extremely rare for a high voltage contactor to fail.

I am wondering if there is some kind of trouble shoot flow chart, that I can follow to figure out my problem.

I've been charging my 12 volt battery on a charger when I get to work, charging it, then driving it home. Then putting it on the charger again, over night. I look like a asshat every time get to work and open my hood to put my "trouble car" on the charger. I have to smile and say, it is worth it to save the money driving so far. But I've killed three 12 volt batteries, and I know the part store guy is wondering why I haven't fixed the problem yet. I've even run a large gauge cable from the 12 volt battery to a much larger 12 volt battery that sites on the floor of the passenger seat to extend my range. But as I'm sure you know, that is not a great idea; for many reasons.

I'm just wondering if we can come up with some kind of over arching trouble shooting flow chart to check every point in the system.

I really like this car, but I haven't been able to drive it at night, use the A/C, use the stereo, or really take much of an enjoyable drive for almost a year now, because I'm always watching the little voltmeter wondering if my battery is going to crap out, 20 minutes from home in a rural area.

How can I/we make sure all the ground straps are really where they need to be? Is there some kind of jumper I can use to go point to point, and see if the car will magically start charging?

The IMA battery is pretty much pooped out. Could that be the core of the problem? Could I have multiple problems.

Help, please.

I really want to feel the joy of having this car working. And I feel FAR from that point right now.

 

[retepsnikrep]

If the IMA battery is really bad the dc-dc converter will be commanded to stop operating and the 12v battery won't be charged.

There are lots of ways round this and others will chip in shortly..

 

[Shane M]

Try this to diagnose the other parts quickly: turn off the IMA battery, take the big metal lid off, and unplug the MCM and BCM computers. Start the car with the 12v battery and see if it charges. With that disconnected the DC-DC converter should charge the 12v below 4000rpm.

 

[Finelin]

Good way to see if your DC-DC converter is bad is cut white green wire on the battery control module. This will keep the dc-dc always on and charging. I just went through this with my gen 1 insight and had a bad dc-dc converter. Another way you can check if you have a bad dc-dc is do a hybrid battery by pass. If your hybrid battery is blah, by passing it will let you at least drive the car (with out hybrid power of course)

 

[Stimie]

Try this to diagnose the other parts quickly: turn off the IMA battery, take the big metal lid off, and unplug the MCM and BCM computers. Start the car with the 12v battery and see if it charges. With that disconnected the DC-DC converter should charge the 12v below 4000rpm.

Apologies and not trying to hijack your discussion Insight to the Hybrid Era.....

Thanks for the reply Shane. I was experiencing the same problem as Insight to the Hybrid Era. I followed your suggestion and unplugged both the MCM and BCM control modules. When I did, the battery light did turn off on the instrument cluster so my assumption is the DC-DC converter is charging the 12 volt battery now. After unplugging the modules, I have a code that has popped up PC-1644. My question is what would be my next step for diagnosing the 2 control modules to narrow down what is wrong, etc.... Any suggestions or advice would be appreciated.

 

[Shane M]

Apologies and not trying to hijack your discussion Insight to the Hybrid Era.....

Thanks for the reply Shane. I was experiencing the same problem as Insight to the Hybrid Era. I followed your suggestion and unplugged both the MCM and BCM control modules. When I did, the battery light did turn off on the instrument cluster so my assumption is the DC-DC converter is charging the 12 volt battery now. After unplugging the modules, I have a code that has popped up PC-1644. My question is what would be my next step for diagnosing the 2 control modules to narrow down what is wrong, etc.... Any suggestions or advice would be appreciated.

Glad that got you somewhere! You do get obviously an IMA light and a check engine light by doing that as there is a whole system no longer working, but as for diagnosing issues with the computers themselves you're going to have to consult some more knowledgeable folks, I'm not to sure about what to do there.

Also, if someone does end up needing a DC-DC converter I believe I have a good one in my basement from my parts car.

 

[Stimie]

Glad that got you somewhere! You do get obviously an IMA light and a check engine light by doing that as there is a whole system no longer working, but as for diagnosing issues with the computers themselves you're going to have to consult some more knowledgeable folks, I'm not to sure about what to do there.

Also, if someone does end up needing a DC-DC converter I believe I have a good one in my basement from my parts car.

Many thanks again Shane. For what it is, I am not getting an IMA light on.... Only the check engine light now. And I did go as far as to replace all the fuses underneath the dashboard and in the engine to confirm that all are working. However, I believe that i read somewhere that there may be an inline fuse back in the hybrid battery box in the rear. That I have yet to locate and check.

If anyone else can offer up any advice as to how to diagnose the control modules, I would very much appreciate any suggestions.

 

[NewOwner]

Well what codes are you getting from your CEL?

 

[Insight to the Hybrid Era]

If the IMA battery is really bad the dc-dc converter will be commanded to stop operating and the 12v battery won't be charged.

There are lots of ways round this and others will chip in shortly..

the IMA is strong enough to start the engine. Thats all I know about it.

 

[Insight to the Hybrid Era]

Glad that got you somewhere! You do get obviously an IMA light and a check engine light by doing that as there is a whole system no longer working, but as for diagnosing issues with the computers themselves you're going to have to consult some more knowledgeable folks, I'm not to sure about what to do there.

Also, if someone does end up needing a DC-DC converter I believe I have a good one in my basement from my parts car.

how much do you want for the dc -dc converter. Is there a way to test it before I might buy it?

 

[Insight to the Hybrid Era]

Try this to diagnose the other parts quickly: turn off the IMA battery, take the big metal lid off, and unplug the MCM and BCM computers. Start the car with the 12v battery and see if it charges. With that disconnected the DC-DC converter should charge the 12v below 4000rpm.

The MCM and BCM are these two guys right?
They were unplugged when I got them.
the 12 volt battery didn’t charge when they were out.
I’ve tried it several times with them both plugged in and unplugged

 

[Stimie]

The MCM and BCM are these two guys right?
They were unplugged when I got them.
the 12 volt battery didn’t charge when they were out.
I’ve tried it several times with them both plugged in and unplugged
View attachment 99394

Take the styrofoam cover off of the module and you will see that it is only one of two modules. They will be marked on top of them which one is which. And I removed the plugs on both sides of the modules. Not only the two that you are indicating.

 

[Stimie]

Well what codes are you getting from your CEL?

Hi NewOwner,

I indicated earlier, the only CEL code that I am getting is PC-1644.

 

[Gasoline Fumes]

I am not getting an IMA light on

With the MCM unplugged, you won't get an IMA light.

 

[Balto]

For some reason as I layed in bed to go to sleep this thread popped into my head and brought back a memory. I could be recalling wrong so please someone correct me if I'm wrong, but I'm pretty damn sure a 1644 can be caused by a blown 12v fuse(not the 100A one) on the junction board of the IMA pack right? I have a vauge memory of one of my insights tossing that code and it turned out the fuse just blew.

 

[Stimie]

For some reason as I layed in bed to go to sleep this thread popped into my head and brought back a memory. I could be recalling wrong so please someone correct me if I'm wrong, but I'm pretty damn sure a 1644 can be caused by a blown 12v fuse(not the 100A one) on the junction board of the IMA pack right? I have a vauge memory of one of my insights tossing that code and it turned out the fuse just blew.

Thanks Balto,

I was thinking that I would go back into the IMA pack to check for fuses there today in addition so that I can take a picture for "Insight to the Hybrid Era" and show him what the two modules look like in addition to the wiring harness plugs and help him get his unplugged and further along.

 

[Stimie]

With the MCM unplugged, you won't get an IMA light.

Yeppers. Thank you.

 

[Stimie]

Insight to the Hybrid Era

Here are a couple of pictures that show the two modules.

 

[Gasoline Fumes]

They will be marked on top of them which one is which.

I was wondering what you meant by that. Somebody added those labels. Honda only put the part numbers on the one edge.

 

[eq1]

Take the styrofoam cover off of the module and you will see that it is only one of two modules. They will be marked on top of them which one is which...

Funny: fyi, those labels don't come stock.

A couple quick points on a couple things mentioned:

-Yes, you should be able to get 12V charging if you turn the pack off and pull the two plugs on the front of the BCM - with a bad/empty pack, i.e. it should take the bad pack out of the equation. So if you can't do that and get 12V charging it would point to something other than a bad pack. Note that some cars don't start if the MCM is unplugged - mine didn't when I did that bypass a long time ago.

-The WHT/GRN wire mentioned earlier: usually it's cut or removed from the DCDC connector, not at the BCM or MCM, and it doesn't permanently enable the DCDC, it only ensures that it doesn't drop into low power mode (~12.2V vs. ~13.8V).

-It takes very little pack functionality to start the car with IMA. I'm pretty sure you can have a pack that's low enough to disable the DCDC, yet it will still start the car. On the other hand, you should be having other bad pack behavior, such as 'neg recals' and such, if the pack is really that low and/or imbalanced, etc... When I run the pack really low, which I do a lot, I usually get a neg recal (effectively empty) followed by DCDC disable shortly thereafter. I can still come back to the car in that state and start with IMA. Whenever I've tested/measured stuff when doing this, DCDC shuts down when a tap has reached about 14V. Since it hasn't always been exactly 14V, seems like the cutoff might be voltage slope, not an absolute value. But it's possible my measurements/timing and such haven't been accurate enough, it could be an absolute ~14V threshold...