High pitch noise, no brake fluid, loss of power after 12v battery replacement

I changed the 12v battery in my wife's car the other day because it kept dying. Immediately all the abs lights came on. From what I read I thought this was normal and that it meant the light just needed to be reset so she drove it across town for an errand. It lost power twice on the freeway but did not die in 100 miles. When she got home it had lost all brake pressure and she could barely brake. I looked at the battery closer and noticed that the cca's were 410 and the original battery was 310. I then swapped the battery with a new one from autozone with 340cca. Immediately the car starts making a loud ringing noise and the red triangle comes on. I hooked up the code reader to find a barrage of codes and erased them which turned off the noise. Anytime I hit the brakes or open the door it starts making noise again. Checked the brake fluid it was bone dry. Checked the fuses and they were all good. I believe her brake actuator went out but I figured I'd get a second opinion before I pony up for a new one.

 

Oh that makes total sense! I believe there was some fluid on the inside side of the driver side rear tire. I'll check when I get home in a couple hours. So I will repair the leak, bleed the system with techstream, clear the codes and then see if the codes for the actuator come back. Thanks a lot guys I was under the impression that the fluid loss was a symptom of the actuator going bad. I'll update you this evening.

 

Tracked the leak down to a wheel cylinder that failed. Been trying to get techstream going so I can bleed the whole system. Had some technical difficulties getting the software setup. My dad had the Chinese bootleg version so I had to use an old laptop and reformat with winxp. Of course I have to pull pictures off for my wife so I'm waiting on 2700 pictures to transfer. Will update tomorrow.

 

Well I replaced the actuator and did the bleed with techstream. All the codes went away. I got 100 ft before another slew of codes came in. I spilled a little bit of coolant on the internal left side of the inverter because i was having a heck of a time with the service plug and inverter cover allignment. I believe that killed it because I got code p0a78-386 then checked connections and hooked a voltmeter to the I9 connection which gave me .4 volts and dropping with the ignition on. I'm heading to the junkyard for a new inverter now. What's weird is that the hybrid battery now shows 80% after a I disconnect but when I start it, it goes down to one bar after a about 30 seconds. The new inverter is only $70 so I figure I'll try that.

 

After replacing the inverter I seemed to have fixed all my problems. No codes and I took it for a short test drive However I noticed that the coolant pressure was low when I went to do a bleed on that system. So low in fact that the pump wasn't pushing the coolant all the way back into the reservoir. I believe that may have contributed to the part failing and i will be replacing the inverter pump and flushing before taking it back on the road.