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Discussion Starter #1
Hi all. I'm new to the Insight world. I just recently picked up a 2001 CVT with 140k. The owner stated it did need a new battery, along with brakes. The car was likely not used much recently, as brakes were rusty etc. I took the car on a test drive and there were no fault lights (his ad stated it did however). I checked and all IM readiness was good, so it must have been driven some successfully without an IMA fault. I bought and drove the car home (about 75 miles when all said and done). IMA seemed to charge/discharge as expected- it still had the original pack.

Fast forward a week or so - put plates on the car and took it on a drive. It was very wet outside. IMA light came on after about 15 minutes of driving. I figured this was due to the battery pack so I didn't even check the code. It was already my intention to buy a replacement pack with new cells.

I installed the pack, and upon starting the car, the IMA fault was immediate. I get code P1438. That is the only code present doing a scan (generic scanner). As others have exhibited, I did have a bit of water in the spare tire well.

My question is: Where do I start to diagnose this? I found some info on the forum, but I am unfamiliar with which modules is which, the names of the various components, etc. This is my first foray into a hybrid.

Any help would be appreciated.

Kris
 

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It appears the code is for the MCM, the silver box on top of the Hybrid battery on the right side it has 4 electrical plugs toward the front of the car.
Please double check the connections and be sure they are plugged in and there are no bent pins or corrosion in the plugs/MCM. Then clear the codes and see if if the code comes back.

You say you replaced the Hybrid pack, was it new sticks, and who supplied it?

Scott
 

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P1438

That might be bad news. :(

Open up the IPU (rear compartment) and measure the voltage between
MCM connector A Pin 13 FOT green/white wire and
MCM connector A pin 24 GND brown/yellow wire

It should be ~5v with ignition on.

Try unplugging and replugging the MCM connector A as Scott suggests in case you have pin corrosion or dampness etc...

If it still faults immediately after clearing the system with a proper 12v battery disconnect, then you likely have an IGBT fault or bad connection inside the MDM.

See this YT video..

[ame]https://youtu.be/mTKjnkC0m7A?t=38[/ame]

Lots of scrap MDM's in breakers yard in the US so not the end of the world.
 

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Discussion Starter #6
Thank you, I will meter out those connections (hopefully) tonight after I get home from work, after inspecting the pins. I did double check to ensure it was seated in the socket a couple of times, and there was nothing glaring at me as far as corrosion either, but I will take a much closer inspection today. Would any of the infamous ground straps be suspect in this case? Also, what is (or where is) the IGBT?


I bought a rebuilt pack with brand new sticks from Best Hybrid Batteries in Illinois. He offered a 3 year unconditional mileage warranty, and he was only a couple hours away.
 

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Would any of the infamous ground straps be suspect in this case? Also, what is (or where is) the IGBT?
Always worth checking the grounds but unlikely to be the case IMHO.

Check my YT channel and videos.

The IGBT is in the MDM, which is inside the rear compartment.

 

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Discussion Starter #9
mcm or mdm

...just a follow up to the posts above. When I check for the 5v, if I do not get 5v, I can deduce that the MDM is the culprit. If I do get 5v, I can deduce the MCM is the culprit (both assuming connections are ok). Is that correct?
 

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Discussion Starter #11
Which connector is connector "A" on the MCM? None are labeled that I see, and i only see random numbers on each plug (eyes aren't good enough I guess).

Also, where specifically is the IGBT located?
 

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Discussion Starter #12
Sorry, I missed the comment above that the IGBT is located in the MDM.

Just looking for which connector on the MCM is connector A. Time for a camera.
 

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Discussion Starter #13
Tested for 5V

Well, I tested for 5V at engine running. I am not getting the 5V, so I am guessing it is the IGBT in the MDM. I also ohmed out the connection between the MCM and the MDM - that connection is good. No visible scaling or oxidation on the connection. I do get 5V to the wire below (I saw to check this in some other thread where someone said to cut and jump it, which I have no plans to do).

Based on this, getting the MDM is likely the right route?
 

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It's looking like it. One final test before you pull the MDM out..

Cut the green/wht FOT wire and connect the MCM end to MCM connector C Pin 24 (coincidentally also a green/wht wire) Leave the other end of the FOT wire unconnected.

This interrupts the fault signal from the MDM, and pulls the MCM input upto 5V to give the all is OK signal.

The fault code should disappear.. However

There are two possible outcomes now..

1) The fault was in the temperature monitoring section of the VCM and the IGBT is not locked out so the car may now work.
2) The fault is in the IGBT and IMA remains locked out so it will have to be replaced.

You may get lucky..
 

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I will give that a shot. I think it will be more for learning purposes. I can get the whole MDM assembly for 100 bucks. That said, if it is in the temperature monitoring section - it is relatively low risk to drive it this way from my understanding, as they are not known to actually overheat. Is that correct?

Kris
 

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Correct and the actual MDM fan control section is probably still working or you would have another fault code.
Please ensure you report back with fault finding results and when you have fixed it.. Thanks
 

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Discussion Starter #17
I jumped the wire. The P1438 went away as expected. I now get a P1576 Motor Drive Module (MDM) voltage signal circuit low input. IMA light still present.




Correct and the actual MDM fan control section is probably still working or you would have another fault code.
Please ensure you report back with fault finding results and when you have fixed it.. Thanks
 

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Discussion Starter #20
MDM Worked

Thanks again for all your help. I received and installed the replacement MDM yesterday, and also re-properly connected the 5v wire to the MCM. Everything works as it should now!
 
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