Help needed with U0146

Recently got an 08 Prius from a friend, vehicle has a 150k miles on her with a red triangle. I hooked up the techstream and got only U0146 (hybrid control). U0146 points to (Lost communication with gateway "A" - CAN communication problem between gateway ECU and HV control ECU (no signal input)). Vehicle drives well without any issues except it has the red triangle. Checked the TIS website and information pointed to a potential failure in multiplex communication network. I just want to know if anyone here has had any experience with this code. Some internet researches pointed to the ground connection to the gateway ECU, body ECU issue, bad IG1 relay (though this tested ok) however, since the code is pointing to "no signal input to HV Control ECU", i am leaning towards checking the resistance of the connection between the HV ECU and the gateway ECU for continutiy.

One more thing, when i did a CAN bus check on techsteam, a bunch of systems (can't remember which ones now) came up in red indicating there may not be fully communicating on the network.

Many of the posts here on PC that i have read about have U0146 alongside a bunch of other codes indicating a wider issue but not just U0146. I had another gateway ECU lying around somewhere and decided to change the gateway ECU (Part No. 47050) with the same result.

I am about to dig into this harness in next few days, but was just wondering if anyone has had this same situation or may have ideas that i can lean on.

 

Yes, i have done that using T/S and also by removing the 12v battery and it did come back. I also changed the gateway ECU with another one lying around like i mentioned earlier but no luck.

 

Turns out it was the body ECU, once it was changed, code went away.

The repair manual for the 2010 manual was used to check for DLC3 branch wire and CAN No. 1 Bus Main Wire (CANH - CANL) which was 61 ohms, check for short to GND in CAN No. 1 Bus (CANH, CANL - CG which was 1M ohm each, check for short to +B in CAN No. 1 Bus (CANH, CANL - BAT) which was 6.5 ohms. Also checked the continuity of the wire from the gateway ECU to the center connector 2 for Multiplex Communication wires (MPD1 & 2) which were all good, checked ground connections IH and one other one, removed them, sanded and applied contact enhancer. After all said and done, i still had the same code.

So i decided to changed the body ECU and the code went away. Referenced hobbits work http://techno-fandom.org/~hobbit/cars/bodyecu/ ....did not really know if the ecu was bad or perhaps some changeable component on it. There are three relays (IG1, HTR and flasher relays) and two high current fuses (30A PWR and 40A DEF) however, the complete unit was changed since i had it around.
Good to have the car back.