ABS, VSC, (!), BRAKE Lights, Help Please!

Good morning.

I'm a first time poster, but occasional lurker on the forum. Recently my ABS, VSC, (!), and Brake lights all started coming on when I turned on the Prius (2005, ~187k miles, has a reconditioned Green Bean battery that's 4-5 years old), along with a beep. The beep would end, the lights would go off, and the car drove fine, no brake issues. Then this week, the beeping stopped, and the lights came on permanently, but still no brake issues.

Also, for some time my MPG has been low - much lower in winter than usual, and with warming temperatures it hasn't fully recovered. Currently I'm getting maybe 35mpg. In the winter I was getting around 28. Normally I average 42. Took to a dealer a month or two ago and they couldn't diagnose any issues at that time except new tires, cold weather, and old spark plugs. Changed the plugs and it got a bit better. Currently I drive almost exclusively in town, short ranges, 5-15 minutes tops.

From some research online, I've been trying different trouble shooting options. What I've discovered so far:
The 12V battery is showing 11.9V in ACC mode, 10.9-11.1 under load from the headlamps in ACC mode, 11.2 with the power on, and 13.8-13.9 in engine ready. These numbers look low to me, but I'm not sure why they would throw brake codes, or if they are too low. The battery is about 1-1.5 years old - I left a light on over night and drained the last one back in early 2022, but I don't recall exactly when or what brand battery it is.

I did see turbulence in the coolant tank and heard what I thought was the inverter coolant pump running. I'm not sure the turbulence was at the level it's supposed to be at, and don't have a way to measure that, except to compare it with videos online. It's hard to see online and in my tank, so I probably can't give any more details than that.

I have not yet jumped the plug to reset the codes and see if they clear.

I had an auto parts store pull the codes for me, and got C1256 and C1391 - accumulator low pressure, and abnormal leak of acc pressure. I have been hearing a weird sound while depressing the brakes sometimes, so I'm thinking that the actuator/accumulator is going. Also, I think my Prius has been making more noises in general lately, including running the engine more.

I have a lot of questions that I hope the smart people here can please help me answer - I love the Prius, but I'm not technically skilled enough to do a lot of work on it myself. I appreciate any help!

Should I bother jumping the pins at this point?
Should I attempt to replace the battery at this time?
Do I need to go to a dealership to verify if it's the actuator/accumulator, or can other mechanics handle this? I moved recently and don't trust the local dealership.
If it's the actuator: I've read that there may be hybrid specialist mechanics who can replace it with a used part to save money - can anyone give me any recommendations on how to proceed, whether it was worth it using an older part, how do I find out what part number I need, etc.?
I'm in the Oshkosh, WI region. I've heard there are some hybrid specialists in Madison, WI. Does anyone have recommendations on reputable mechanics who could handle these issues in my area? I'd prefer not to drive an hour+ with a potential brake issue brewing, and google isn't helping me much at this point.

Again, I really appreciate any help!

 

Dolj,

Thank you for the response. I'll check out those part dealers and the battery charger. To your other question,

"Why hasn't the dealer already advised you of this, did they not do a proper health check scan when you had it with them?"

I have not taken it to the dealer since the lights came on, which was a couple days ago. I do not trust my local dealer - I'm new to the area, but already have heard bad things about them. That's why I'm hoping to find recommendations of decent local mechanics who can handle the task.

When I had it at this dealer a couple months ago, they didn't find anything wrong with the vehicle except old spark plugs. The fact that they had it, drove it, and didn't notice any of these issues, is also part of why I don't trust them very much, now.

 

"If someone has already used a scan tool and told you what the codes are, you already know them, so no pin games are necessary."

Thank you. Saves me some trouble then.

 

Bisco,

There were no codes at the time it was at the dealer. I got the codes from an autoparts store when the lights came on and stayed on a couple days ago.

I understand that trouble in the ECU can lead to the lights coming on. But does it lead to codes C1256 and C1391 specifically, or would the codes be more related to the ECU?

 

I know virtually nothing about cars beyond what I read in forums like this. Which grounding wires? Where? How are they cleaned?

 

Thanks everyone. I've got it scheduled to go in to a shop on Friday that I think does more hybrid work in my area, and has a decent reputation (local dealership does not). If I have time I'll try to investigate the wires, but I may just leave that to the folks who know what to look for. I appreciate the advice and leads on cheaper parts!