First the codes:

The following 2 codes show up in my scanner under BCM IMA, IMA battery, TCM, and PGM-FI (fuel injection control module). All say either EP-CAN malfunction, FP-CAN malfunction, or lost communication with IMA.
U0110--pending, confirmed, and permanent
U1205--pending, confirmed, and permanent

ABS codes 61-22, 56-1, both permanent

Body Electrical (Air Conditioning Module) B2990, B2993, B1241

EPS 12-01, 11-02 both confirmed

Hydraulic booster 66-1, 61-1, 63-1, 82-1 all confirmed

According to scanner HV battery sticks are as follows:

1--12.3
2--13.6
3--12.1
4--13.4
5--13.1
6--12.1
7--10.2
8--13.8
9--10.9
10--13.1
11--13.6

Car has not been functional for 2 years (HV battery disconnected during this time). 12V battery light, flashing D drive indicator, IMA and CEL lights all on. When the problem first began, the car would either start normally and function well, or it would start with the conventional starter and all stated warning lights would be on with no IMA system engagement. There was no in-between, no IMA light coming on while driving (only CEL for long-term P0420 code) and no noticeable recalibration. I took it to Honda and they could not replicate the problem so could not determine the issue. Said it was probably the hybrid battery. I was concerned about the 12V battery light since I had already read on these forums it meant the 12V battery was not charging. The service department manager ASSURED me that it was fine to drive, it would not die, it would function as a normal gas-powered vehicle. The car worked better at first and I thought they had inadvertently fixed it by unplugging and replugging connections. On the second day the car died and I was stranded in a parking lot. I had it towed to my regular mechanic, but he couldn't figure it out and said he didn't know enough about hybrids and didn't want to just throw money at it. He did check all fuses and obvious to him electrical connections and all were good. I didn't trust Honda to take it back to them.

It might be worth noting that I drove this car as a delivery vehicle with many short trips, but most of them back-to-back. I drove over 100 miles per night and put nearly 100K miles on it in 3.5 years.

Also, the 12V battery has died in the car within 1 day since it has not been working. It's been on a float charger in the vehicle, and this morning tested at 13.3V right after charging, and it dropped down to about 12V within a few hours. Tested for a parasitic draw with a multimeter, but that stayed between 20 and 21 milliamps when connected for at least 20 minutes. Took the battery out and took it to Advanced Auto and CCA tested good, but reserve health failed. Took it to Walmart where it is still under warranty. They used the same machine and both tested good. Cleaned up posts and terminals (didn't seem too bad) and even after running the car for 5 to 10 minutes to see if there were any code changes, the battery seems to be maintaining at about 12.58V after a couple of hours.

Finally, I noticed the HV battery is a CA3 so it had already been replaced at some point prior to me owning it.

Thoughts on what I should try next? I only got my multimeter and code scanner yesterday, but I'm pretty resourceful and teachable.

 

IMHO, most codes/symptoms listed are caused by disabled DC-DC converter/low 12V due to IMA battery tap voltages being way too low to function properly.

Your IMA battery is beyond completely discharged. Any tap at or below 14.4V is completely empty of any usable capacity. Pretty much to be expected if you let them sit for two years.

Grid charge IMA battery. Reevaluate.

 

I'm willing to try grid charging, but I'm curious about what your thoughts are about when this started 2 years ago? I'm wondering because there were never any codes related to the battery itself, and again, it seemed to work perfectly or not at all then. I could sometimes even start the car and have the IMA not come online, and then turn it off and restart it and it would work.

I also wanted to mention that with the backseat out, every time I start the car, I hear something click in the back immediately before the IMA light comes on. I read somewhere that if the TCM has an issue, it will shut down the IMA system.

The good news is that the local tech college has agreed to take my car to work on labor free for their hybrid class, but unfortunately that class doesn't start until next July. Also, they will charge me for any parts, including a 25% markup. I'm sure they have to go with new OEM parts. They have the technology there to individually recondition each cell. I know I would still need a grid charger after that to maintain it anyway, and I'm thinking if I could diagnose this myself I could probably find used parts for a fraction of the cost.

 

I can't comment on what happened two years ago. I can only comment on the current information presented. Your IMA battery is completely non-functional. Without a working 12V, 12V charging system and functional IMA battery, subsequent diagnostics can be extra challenging to impossible.

The clicking is likely the relay disconnecting the IMA battery from the car due to its poor state.

Next steps:
1) disconnect 12V battery
2) fully charge 12V battery outside the vehicle for at least 24 hours.
3) While charging, inspect engine compartment for damaged/chewed wires.
4) and check all fuses in the two under-hood fuse boxes. Use a continuity tester on each. Visual isn't always enough.
5) install 12V battery
6) with key on, engine off (do not start engine), conduct full diagnostics with your scanner and report all codes.
7) start and idle car for 5 minutes. Conduct full diagnostics with your scanner and report all codes.

 

Okay, the reason I asked is because it has the same codes now as it had 2 years ago when I took it to Honda, and the exact same behavior. They did fully charge the battery at Walmart before testing it, and I have been leaving the charger on it while in the vehicle for some time now. It did maintain its charge overnight not last night, but the night before, while in the vehicle and not connected to the charger. I can certainly disconnect it, but I'm curious about the difference this may make?

I did the contiunuity testing yesterday and all fuses passed (in all 3 fuse boxes). I also did both scanner tests with the key in the on position and then with it running, exact same codes both times.

I know my mechanic looked at the wires but I can try looking again.

I do agree it needs grid charging at this point, but I guess I'm surprised that the IMA light never came on before while I was driving it, and I never saw any battery codes.

 

If U0110 and U1205 are persistent after extended 12V disconnect, I recommend you get a factory manual for your vehicle. There is a pretty extensive troubleshooting tree for that combination of codes. Resolution includes wiring repair, MCM update, MCM replacement, BCM update and BCM replacement.

If the MCM or BCM have failed, the UXXXX codes may be triggered before the IMA can register a fault with the battery.

You can find BISHKO published Honda manuals on CD on ebay pretty cheap.

You can also do a Honda subscription:

https://techinfo.honda.com/rjanisis/logon.aspx

$25 for one day.

 

Thanks very much for your help. It's my (limited) understanding that codes that are labeled permanent will not go away until the computer is able to go through its tests again and determine whatever issue has been resolved--are you saying that an extended disconnect could work to reset the codes in this situation? I had kind of wondered for the other codes if I needed to try to drive around the block several times to see if those would go away. My car is currently not registered because WI started to charge double for the annual renewal fee for hybrids and EV to help make up for their loss in fuel tax (which they use to fund road repairs) so I haven't tried to drive it anywhere, but I could probably get away with several trips around the block LOL.

Also, I took this picture of a ground wire that I don't think is supposed to look like this. If I had to guess, I'd say my mechanic removes the electrical tape or insulation when he was investigating the issues and forgot to recover it. He had t he car over a month (he worked on it during his spare time) and we were both getting frustrated at that point.



Unfortunately my other vehicle is a 2003 Forester 2.5X with the notorious boxer engine head gasket leak. So far it's an external leak, but it goes through a lot of oil which isn't good for the environment, or my wallet for that matter. The used car market is insanely expensive right now, not to mention gas prices being high-- so yeah it would be nice if I could get this car running before August LOL.

It's costing me over 10K per year to drive the Subaru with as many miles as I drive. I figured out that I could buy a used 2013 Tesla Model S for 35K that comes with the free lifetime supercharging...and compared to driving the Subaru that car would pay for itself in 4 to 5 years tops. I'm not saying I'm in a position to do that, but it just kind of blew my mind.

 

Yes. 12V disconnect can reset almost all codes. Step 1 in the Honda manual for U0110/U1205 is "clear the codes."

If they come back immediately, then that means they're real.

Hondas are notoriously problematic on their grounds. The fact that you see clean copper there suggests that cable is fine.

 

Good morning Steve. Regarding a grid charger and discharger system, I was looking at the Prolong system, but it will cost me $745 shipped. Uffda. I'm interested in building my own system. I would like something that has a plug connector where I can leave the wiring harness installed, and something that will show the current voltage would also be nice. I'm having trouble finding straight forward instructions on how to do this, though I'm sure it exists somewhere. I would certainly appreciate your input and a point in the right direction.

I haven't gone out to re hook up the 12V battery and rescan yet, but should be doing that sometime later today and I will post an update then.

 

https://electricvehicleforums.com/fo...charger-32977/