C1345 Code, "Brake," "(!)," "ABS," "VSC" Lights, No Regen Braking

I'm a long-time lurker on Prius Chat and have used the information found here to do my own Prius maintenance for years but I have a situation that I have been unable to resolve.

I bought a 2007 Prius last August. In March I got a P1116 code, a C1249 code, and a C1310 code. I replaced the coolant control valve after I found some leakage around it and, in April, when there was still a check engine light, no heat in the vehicle, and poor mileage I also had to replace the thermostat at which point I also flushed the radiator.

The check engine light went out, however, things still weren't quite right. I would experience a momentary loss of power when accelerating hard and the traction control light would illuminate with any variation in the road surface even with light braking. In May my battery got really weird, rapidly going from 1 bar to half full and then, when I pulled into traffic one day I got the triangle of death, the (!) and VSC symbols, and my Prius went into limp mode. I replaced one module and got it back on the road until I could do a full cycle of all the modules and replacement of two more marginal modules in June.

The battery now seems to be performing nominally and has improved from 48% estimated capacity in May to 93% estimated capacity per the Dr. Hybrid life expectancy test. Unfortunately, the braking issues only got worse and, ever since going into limp mode, I have no regenerative braking, the pedal is soft, and braking is strange with anything more than light brake pressure engaging what feels like panic braking. If all brake pedal pressure is not released as the vehicle comes to a full stop, it stops with a bouncing lurch. At the same time, my mileage has dropped from low 40s before May to mid to high 30s.

After I replaced the first HV module in May and the problem was not resolved, Auto Zone did a code read and pulled a C1345 (Not learning linear valve offset abnormality) code. Additionally, the dash has had the Brake, (!), ABS, and VSC lights illuminated since then. After being gone for work most of the summer, I finally got Techstream working today thinking I would find more codes to help me out but C1345 remains the only active code. Based on what I can find on the forums, I have so far done the following:

• Checked the battery voltage at the terminals: 12.77 V an hour after parking, 12.09 V in IG-ON with the headlights on, and 13.81 V in READY with engine running. Based on what I reading on this 12V battery thread, that sounds like a healthy battery.
• Checked the inverter coolant reservoir for turbulence - good flow visible.
• Checked the brake fluid - just under maximum.
  
• In the main fuse box under the hood, checked every fuse that seemed related to ABS: 11 (HEV), 12 (P CON MAIN), 13 (ABS-1), 18-20 (ABS MAIN 1-3), 32-33 (ABS-1/2) - all good fuses.
• Followed the instructions in post #11 of this thread to test the ABS relays - all relays read <0.2 ohms when closed.
  
• Used a jumper between the CG (#4) and TC (#13) pins in the OBD II port and read the codes. (!) flashed a 66 and 67, ABS flashed a 42, and VSC flashed a 45. In May, checking these codes and following the 8 depressions of the brake pedal in 5 seconds would temporarily extinguish the lights, now the lights return immediately. It seems ABS 42 and VSC 45 aren't in any manuals while the (!) 66 and 67 indicate "Linear Solenoid Valve Offset Learning Undone" and "Linear Solenoid Valve Offset Malfunction" respectively.
  
• Followed the instructions in post #6 of this thread and post #1 of this thread to relearn the linear solenoid by using a jumper between the CG (#4) and TS (#12) pins in the OBD II port. The (!) light flashed slowly for a minute or so while clicking and humming noises came from under the hood and then the light went solid. Unfortunately, there was no change in the lights or the symptoms after the relearning process.

In my research, I have referenced various other threads including but not limited to: YeeHaar! ABS, Brakes Lights, C1203, C1345; ABS Brake Problem: Error Codes C1203 and C1345; Help with 2 digit flashing codes...; and VSC and ABS codes. Unfortunately, I'm out of ideas at this point.

Do I have any other options before I start looking at replacing a brake actuator? Is there a way to troubleshoot the actuator and confirm it as bad before I pull the trigger on a replacement?

 

Thank you much for the responses and thank you ChapmanF for your multiple posts on other threads that I referenced during my troubleshooting. After failing to get the learning procedure to take, I headed to the local dealership who also failed to get it to learn; they are calling it a bad actuator as well. Yay me! I had hoped the lack of a C1256 code meant it would turn out to be something else. Now, I have to decide if I drop the $2500 for the dealership to do the work with an $1800 actuator, buy an actuator myself and have them install it for $600, or do the whole process myself. My Techstream install seems to be missing some functionality so I might be stuck having them do the bleed process if I can't get a fully functioning install.