2016 Prius Braking power low warning

Maybe take the car’s advice: visit dealer. There should be codes, and you don’t want to mess around with something like this.

 

Bad accumulator pump? 12 volt battery?

 

Check your brake fluid level. You may need new brake pads.

 

Was anything plugged into OBD port by the way? I’ve had somewhat similar, when I had a Scangauge constantly connected; it was apparently weighing on the connection, causing a communication error.

 

@bisco im having the same issue with my brakes, may i ask how you got to this conclusion " bas accumulator pump"

 

how did you end up with that issue? any repair ideas? anything to recommend like battery replace?

 

@amos; the car needs to be scanned to figure it out; but first you need to test your aux. 12V battery. A low or bad battery will make the car throw out phantom error codes. That's the first thing the OEM Toyota troubleshooting manual tells you to test.
If this issue is intermittent, it should show up in your pending codes on your scanner. When was the last time the brake fluid system was flushed out or has it ever been? A sticky valve or bad sensor could be throwing this error, but without a scan - no-one will know.

Hope this helps....

 

car has 250k, battery is over 6 yrs old now, no dtc codes recorded on my scanner, no check engine light.
it happened twice in past week. first time went by itself after a short drive, of 2 miles with 5-10 mph speed, i iheard some clicking noisses and than all warning dsplays dissapeared. yesterday i drove it 300 mles on average 70 mph, lucky me it happened a minute away from my home.
never flushed the brake fluid.
car has been so reliable 6 yrs of ownership
all is ok again now
thanks for the reply @biomed01

 

What is your scanner? Many can only read the basic ignition/fuel injection system, and ignore errors from the hybrid, ABS or various other subsystems in a modern Prius.

You're not describing a problem that is likely to be in the gasoline engine, so it would be normal to see "no DTCs" from a scanner that doesn't know how to ask about the other kinds of problems.

If you use a good Prius-capable scanner you are likely to find some actual DTCs.

 

most cheap scanners can't access ABS ECU data. In fact, some mid-priced scanners, advertise the fact that it's an ABS capable scanner. Since you've seen this issue twice, there should be at least 2 occurrences locked in your ABS ECU

.

 

My scanner is really cheap and basic. Not detecting any abs codes. No codes were there and I also don't have a check engine light.
I will replace the battery tonight just waiting for traffic to clear here in l.a rush hour now

 

I will go to AutoZone and check with their scanner. I'm hoping changing the 12v will finish this. Didn't find any posts here showing there's a serious problem. Do you know of any members reporting real abs issue?

 

c1241- low/ high power supply voltage
c1252 - brake booster pump motor on time abnormally long
c1253- pump motor relay
c1256- accumulator low pressure
c1300- skid control ecu malfunction
c14D5- accumulator pressure sensor stuck

i will add some brake fluid, it is below the middle ine of high low but not touching the low line.
my brakes are originals never changed, 250k miles
and change the battery tomorrow.

 

Yep, get the battery checked out. Low power could be the root of those issues popping up. I'd also flush out the braking system with clean new DOT 3 or 4 fluid; in-case there's debris floating around in there intermittently jamming up the sealing rings and valves - causing internal cross leaks.
The brake fluid is half way down, because your pads are worn half way down or more. It's an old school way of checking brake pads without pulling the tire and doing a physical exam. The assumption is that there's no braking system leaks and nobody has topped-off the brake fluid. If you replace those pads and push back the pistons, the reservoir will overflow.

Good Luck.....

 

duplicate

 

Makes sense
Is there a big difference between dot 3 and 4. I have one qt of dot 3 here

 

For the average driver? No, it doesn't much matter.

The important part is that your new fluid should be coming out of a sealed bottle so it hasn't had a chance to absorb any moisture from the atmosphere. All DOT 3/4 fluids eventually go bad with water contamination from natural humidity.

If you use some out of a jug that was opened years ago, it's not going to be much different than what you're bleeding out.

 

If you're sure the brakes are original, you might want to check for pad wear before adding fluid. If you fill the brake reservoir than install new pads you might need to remove the fluid you put in it so it doesn't overflow when pushing back the brake pistons to make room for the new pads.

 

Problem happened again, 3rd time now. Took 300 miles of driving. This time I didn't apply brakes. Brakes became stiff .it came by itself. I was on the freeway late at night . There was no traffic. @bisco you mentioned bad actuator pump. I have 6 codes here now c1253 is the pump motor relay.
C1241 c1252 c1253 c1256 c1300 c14d5.
@ChapmanF any ideas?