Honda Civic 2009 - U1205 and U0110 Codes - Cold Weather Problems
 

Background: I started having issues with my IMA system last winter when the weather starts getting cold outside. The IMA light, 12V light, and sometimes the green D would flash. Many times after the car warms up it would return to normal operation. I managed to make it past last winter and the vehicle returned to normal throughout the warmer months. Now that its getting colder again the car is doing the same as before. The codes are U1205 and U0110. My 12v light does not turn off in the 1500-3500 RPM range but the DC to DC converter does supply power to the car - and I believe its charging the 12V (although sometimes it doesnt seem like it does as well).

I took the car to a local mechanic shop and here is the diagnostics from them:

"
Codes found in Hybrid module, Engine control module, and Power steering module. U1205- IMA-CAN Malfunction. Check
10 amp fuse for the cooling fan power circuit per diagnostic tree. Fuse checked good. Check same circuit for short to
ground and a short to voltage. Circuit checked good. Check voltage drop on cooling fan circuit. Circuit checked good.
Operated cooling fan manually. Cooling fan worked on all 3 speeds but there is a lack of air flow. Check CAN data lines for
any shorts that would cause loss of communication between modules. CAN lines checked good at 60 Ohms. 12-01 Motor
Power Supply Voltage and a 11-02 Battery Voltage. Both codes indicate low 12 volt battery voltage. 12 volt battery was not
being recharged by the vehicle because of the Hybrid system failure.
Perform insulation test on Hybrid battery power cables. Cable test good from the battery to the inverter/converter. Voltage
in hybrid checks fine with 15.8 Volts per cell. U0110 F-CAN Malfunction- MCM Internal Circuit Malfunction. Code indicates
internal module failure. Module is integrated with the hybrid battery.
Recommend replacement of hybrid battery pack and the hybrid battery cooling fan cleaning service.
"

Would like any other insight and thoughts on what I can do to fix the issue. Is it a battery problem or a module I can replace?

Re: Honda Civic 2009 - U1205 and U0110 Codes
 

Not sure where you're getting your information, but it's not consistent with the information in the Honda service manual. Those two codes together have a 40 step diagnostic tree.

It's either a broken wire, cold solder joint, or a MCM, BCM or PCM malfuction. If you want to solve your problem, you should buy a manual:

https://www.ebay.com/itm/2006-2008-2...M/152721238615

Re: Honda Civic 2009 - U1205 and U0110 Codes
 

The above diagnostics were done at a local mechanic shop. They recommended replacing the battery at a cost of $3300.

Re: Honda Civic 2009 - U1205 and U0110 Codes
 

Your response suggests that you think it should change my position. It does not. Please refer back to my post. I clearly stated that the causes for those codes are either PCM, BCM/MCM or repairing broken wires/cold solder joint (analogous to a broken wire INSIDE the MCM/BCM or PCM). At no time did I indicate that IMA battery replacement was indicated for those codes.

Buy yourself a manual or take it to the dealership. Your "local mechanic shop" appears to lack competence in this matter. The "module" to which they refer is NOT internal to the battery unless the HONDA SERVICE MANUAL is incorrect (it's not).