2006 Prius VSC, Brake, Master Warning, and Hybrid Light on - HELP!

You need to check the battery with a load on, like headlights, after it has sat over night. Then check the value with car in ready mode. So three values are needed, the one you reported (12.1V), under load, and car in ready mode.

I will bet the battery is original, and that it is at the end of its life. It can cause strange things to happen.

That may not be all. Your code reader won't read any of the Prius specific codes, so you need to get a scan by the dealer, or get one that that does the job. If the inverter coolant pump has not been replaced, it probably needs to be done. Post any info back here. Also, place your location in your profile to help with further recommendations.

 

Yes, at 11.8V, that battery has reached it's end of life. You won't get more than 6 years of life from a battery, and have a reliable vehicle. At that point there is a good chance for internal plate to plate short, which is not recoverable.

 

The inverter pump is checked by taking off the cap from the coolant reservoir, which is next to the inverter on top of the engine. With the car in ready mode, look for ripples on the surface of the liquid. If none, then the pump has failed.

The pump you hear after shutdown is the coolant heat storage pump. It takes hot coolant from the engine and stores it in a thermos for later use in preheating the engine at the next start up. It should sound smooth. If it sounds like there are bubbles in the system, then perhaps the engine coolant loop has not been properly purged. Those pumps have also been known to fail, but they do not cause performance issues, just a delay in engine warm up.

 

You can get blink codes from the ABS system by shorting Pins 4 and 13 of the DLC3 connector. Search for "ABS blink codes", for ex:

ABS, VSC Lights... Weird!! | PriusChat

It is very important to get the DTC's that are present before making any decisions. Not sure why Torque does not read anything. Get the "mini VCI" on eBay, it will read the ABS codes.

 

Also, mail delivery on our bumpy, rocky roads is via Prius, and it has fared OK in terms of suspension and under body. Just go slowly and pick the best line whenever possible. 4wd pickups that bang along quickly, full of stuff, do wear out ball joints here as well.

 

The blink codes are in the service manual. I can look them up if you list what you have. There's a bunch of them. The service manual for the brake control system is on the Toyota tech site. Not sure where else.

The codes are in groups of fast blinks, separated by 2.5sec. pauses, which result in 1, 2, or 3 digit codes, blinked out sequentially in ascending order. For example, the speed sensors have a range of DTC's: 31-39, with additional INF codes 251->262, 265->275, 277->288, 290->301 for the four different wheels.

 

DTC 36 - Foreign Object is Attached on Tip of Front Speed Sensor LH
That would seen like your intuition is correct. Pull the left front wheel and have a look.

I don't see those ABS or VSC codes in my data. Maybe someone else can chime in here. But they may be related, so fixing the first may turn off the others.

 

This may be a late response but i got the same lights while using my elm327. I got a defective unit making the codes pop up every time i started the car. I removed the connector and the vsc/abs ligths went away. I did not get the master light though.