IMA Diagnostic Codes Mystery
 

Hi All,

Just got good deal (i think) on an 07 HCH2 with 156K. Had a bunch of lights on when I got it, but having read these forums I replaced the dead 12V battery and cleared the codes (which were U0110, U1205, and P0A78). Worked for a few days and then the check engine light is back on with only U0110 and U1205.

Shortly after the car had been idling, I Checked the voltages for the hybrid battery pack which was replaced at 70K miles in 2015 and they were good!
Battery Type CA2.

6-14: 15.55
14-5: 15.54
5-13: 15.54
13-4 15.51
4-12: 15.51
12-11: 15.53
7-1: 15.53
1-8: 15.51
8-2: 15.53
2-9: 15.54
9-3: 15.51

Noted the most recent maintenance record for the vehicle (from honda dealership) mentioned a replacement of a 10A fuse (didn't say which 10A fuse other than "1310" not sure what that means if anything) along with U0110, u1205, and P0A78 codes. Found this webpage :IMA DTCs U0110 and U1205 Set with Fuse No. 61 Blown – 2006-2011 Honda Civic Hybrid
talking about it could be a bad IPU fan.

Removed the IPU electronics and fan. Fan seems to be in good working order, not clogged, nothing unusual about the circuit board. Checked the 10A IMA fuse, still good.
I think I read it is a high voltage fan so I'm not sure about just hooking a little battery to it to test it. If no way to test, I was thinking once I put it back together I could drive on freeway with AC on high and windows down to try and use as much power as possible, maybe that will get the fan in to high mode and blow the fuse which would be a sign to replace fan. Meaning I would have to take the IPU apart a 2nd time :/

I don't know much about electronics. Is there an easy cheap way to test the fan motor itself before putting all this shtuff back together?

Recommendations on whether or not to short the fan (as mentioned in other threads) to keep it on high always for better cooling?

Recommendations on troubleshooting these codes? Might it be an electrical short that isn't a big deal? Idk how to track down an electrical short but I can learn.
P0A78: Inverter/Converter Assembly
U0110: BCM/MCM
U1205: BCM/MCM

Taking the codes at face value would mean replacing electronic components. Although I can obtain used IPU electronics and fan fairly cheaply from a guy parting out his HCH2, I am hesitant to start switching them out because of all the software updates/compatibility issues I have read about.

I'm averaging 40.1 mpg for the first 50 miles or so I've driven it, which includes some city driving as well as some freeway. I do live at the top of a very hilly road. Should I be expecting better MPG? The display is showing both assist during acceleration and regen.

Sorry for the long post, thanks for reading if you made it this far!

Re: IMA Diagnostic Codes Mystery
 

Diagnose and troubleshoot like a pro:

https://www.ebay.com/itm/2006-2007-2....c100005.m1851

Agree taps look good.

40mpg mixed, particularly with elevation changes sounds about right.

Re: IMA Diagnostic Codes Mystery
 

Thanks for the quick reply. What are the tools and materials for shorting the fan so it is on high? I guess if I short the fan so it is on high with everything else hooked up that might give the opportunity for the fuse to blow which would lead me to replace the fan.

Also remembered another, possibly unrelated item. The engine temperature readings I'm getting I think are no good. The temp readout on the dash seems to be in the middle without changing at all, and I got a weird reading on my OBD app as well.

Re: IMA Diagnostic Codes Mystery
 

Are the IMA software updates stored on the IPU electronics or elsewhere? Would it hurt to replace the whole IPU electronics unit? Just not sure about this battery/software update compatibilty thing

Re: IMA Diagnostic Codes Mystery
 

Troubleshoot your problem with a manual. Don't come up with random ideas that will likely just cost you money, not solve your problem, and likely introduce another issue.

Re: IMA Diagnostic Codes Mystery
 

I smell an eBay seller!! I don't have a CD drive so the service manual-on-a-disc isn't readily helpful to me. However, for anyone else who happens to come across this thread. I did find a useful resource, I think it may be an excerpt from the Honda Service Manual:

https://www.scribd.com/document/2717...-Hybrid-System

Re: IMA Diagnostic Codes Mystery
 

Don't see your message anymore, but I see it in my notifications.

No. I'm not an ebay seller. I'm showing you where I got mine, and I can't see the scribd link you sent because that's blocked on my current network. I'm sure you can find access to an optical drive somewhere. From that point, you can copy the PDF wherever you like.

If you took the time to consider or look at the fact that of my 2400+ posts, there's zero evidence that I have any financial motivation whatsoever. My goal is to provide assistance. You need a manual. Period. I don't care where you get it in the slightest, but I don't appreciate BS accusations.

The diagnostics for that code is very involved with lots of detailed measurements. The manual is the best way to troubleshoot, so that's why I've stuck with the recommendation.

Get a manual.