I have a 05 prius with 144k miles and after my triangle of death appeared it said battery block 1 becomes weak so U order 2 refurbished units off ebay with 6 month warranties so I remove my hv battery and place on bench and test all 28 cells and they are over with 8 volts each and I replaced both batteries in block one anyway and guess what it says that the 2 cells I replaced are becoming weak or 1 of them is so any advice on what could be causing my car to throw codes saying battery block 1 becomes weak with good cells in them? Also I changed out block 1 LAST week and charged and load tested block 1 only for fail within a day. I firmly believe my cells are fine because when I read live data when driving my block 1 cells are in line with other blocks so I'm lost any help would be appreciated.
How do the connections look? Any issues with the wires or harness around the block 1 connections? What Torque are you placing on the connection? What are you using to load test as well as charge?
I cleaned all connections with toothbrush baking soda water I just snugged them down I didn't use my torque wrench but there not loose nor over tightened but Its the same as b4 I tore it down first time block 1 becomes weak and I'm using 2 amp charger and load testing with headlight with load about 2 minuets and documenting the voltages and all cells seem to be holding good.
Is it possible I have a bad hv ecu? The hv ecu reads the battery voltages and is it not responsible for throwing the code if it's .4 volts off?
What are you reading the codes with? If Techstream, are there any other codes? If it is the HV ECU, there should be other codes.
Are you changing out the right modules? Block 1 is the 2 modules furthest from the ecu. Block 14 is the two modules closest to the ecu. Does your scanner have the ability to look at freeze frame data? The P0A80 will have freeze frame data that you can look at to see the voltages at the time the code triggered. I also seem to remember these codes (C1259 and C1310) popping up on another members rebuild. Loose connections on the module studs if I remember right.
Not mentioned yet is go to the HV ECU and pull and inspect voltage sensor harness plug. Sometimes corrosion that starts at the bus bars will travel down the voltage sensing wires into the ECU... Most likely that's not your problem, but it's one more thing to check out...
Yes blocks furthest from ecu I will check for freeze frame since this is brand new scanner. Thank u and all post are tight
Do yourself a favor and get an inch- pound torque wrench from somewhere. They are pretty inexpensive at harbor freight. If your gonna go down the path of module replacement you will use it... Probably several times a year.
