Hello have a 2008 Honda Civic hybrid with 63550 miles.

The issue I'm having is that the 12v battery is not charging, replaced the 12v battery with a new one and it still won't charge. The red battery light is still on. And the only code I get is P0A94. Dc-dc converter output low voltage.
The hybrid battery is at 185v
The 12v battery is at 11.8v (I will have to recharge it)
The voltage at the dc-dc converter is at 11.8v
The voltage at the fuse box is 11.8v
I checked all the fuses under the hood, all good are good.

The DC-DC converter part number is 1c800-rmx-034
I replaced the dc-dc converter with a new one, and it still didn't fix the issue
I put in a new battery, not fix
​​​​​​the scanner says it could be a fault in the BCM (battery condition module; part number: 1k100-rmx-a07 ) but how would I be able to check it out?
THis is not my car, but for a customer and I don't want to keep throwing money into it. Thanks

 

Did you check the continuity of the fuses, or just do a visual?

Are there any issues with the IMA battery?

Do you get good 12V voltage when you hold 2000rpm for 30 seconds?

 

Yes I checked continuity with a multimeter on all the fuses under the hood and the relays in the back where the hybrid system is. All good. No ima battery light. When holding rpm at 2k the 12v battery quickly drops in voltage.

I suspect that the DC-DC converter that I bought might be bad.
I got a second opinion from a hybrid specialist, he said it might be another bad DC-DC converter.

 

Replace DC-DC with NEW or salvage?

 

Bought the replacement from eBay. Though the seller said " most parts tested and work well" but this would be like 3 out of 4 times I've been shafted buying automotive electronic parts off eBay. If that's the case.

 

They had a high failure rate, so I wouldn't consider it good unless it was pulled out of a working vehicle.. Not sure how you'd test it besides putting it in the vehicle.

 

Ok I bought a brand new DC-DC converter from the dealer, legit nothing. I'm at a total loss. I have no idea what to do.
I checked the fuses, the relays, the power, the ECU pin, what is wrong with this car?

 

What are the conditions of the grounds? IIRC, there are 3 ground cables.

 

Since you’ve already replaced the 12V battery and DC-DC converter, the issue is most likely a faulty BCM or a wiring/connection problem between the hybrid battery, DC-DC converter, and 12V system. The P0A94 code indicates the DC-DC output is low, which can happen if the BCM isn’t regulating the converter properly. Check all related wiring, grounds, and connectors, and use Honda’s diagnostic software to test the BCM. Without proper testing, replacing parts further could be wasted money. It’s recommended to have a Honda hybrid specialist diagnose the BCM and charging system.