Replaced the main battery replaced 12V battery. Drives great except for the whining on the driver side and the occasional shutter at take of and while driving. Triangle is on and stays on engine light and now break light. Topped the break flood off. Cleared codes and the brake light came back on. Drove it home from Atlanta drove just fine. Lights just freaked me out though. 133,000 miles on the car. well kept. Codes P3120 and P3125 I have a transmission waiting to go in. Any thoughts? Is there any thing else i need to look at? Thanks
DTC P3120 is potentially pointing to a transaxle failure. P3125 can be caused by either a transaxle or inverter failure. Given the noise and vibration drivability symptoms you mentioned in your OP, I think a transaxle failure is a more likely bet. See for example: Luscious Garage | Blog | Gen 1 Prius Transmission Repair, P3009, P3120, P3125
You can look through this forum for information on Prius-aware scanners that can retrieve the 3-digit subcodes that detail the reasons for your P3125. The ScanGaugeII is one such. Swapping parts without having the diagnostic information is a rich person's game. I know I couldn't afford it. -Chap
