Regenerative braking is not working

I just started experiencing exactly the same issue today, it's hot out, and it was charging at around a hundred amps as I descended a steep hill, but by about the bottom of the hill it stopped charging all together and even though the battery is not fully charged it continues to not charge with regenerative braking. It does still charge from the motor however. The fan which cools the traction battery is not running, and it's a few hours later in the day after things have cooled off and it still is not charging via regenerative braking. Torque app does not show any error codes and the car gives no indication of a fault other than that you cannot feel the regenerative braking. I hope this is not early signs of traction battery failure, stressed by rapid charging of the downhill descent. Prius is 2010 3rd Generation with about a hundred twenty thousand miles.

 

I think it is standard behavior for the system to limit maximum charging current from regenerative braking taking into account both battery temperature and state of charge to values less the maximum reached for a cold battery far below full charge.

Is it possible it considers other variables as well?

 

Is your inverter coolant pump working? Look in the reservoir while the car is in ready mode and you should see the coolant swirling.

Also, as I understand it, Torque doesn't come with all the Prius DTC codes. If you haven't installed them, you can find them here on PC with a search.

 

clean the battery fan and grille, the hybrid battery may be on its last legs.

 

I verified that the inverter coolant reservoir does swirl when the car is in ready. This was a great suggestion however.

I have also verified that the radiators are clear of debris.

I'm continuing the diagnostic under dedicated thread which interested parties can find here: Regen disabled and engine runs constantly in warm weather. | PriusChat

 

Hey, I know, dead thread.


But I've recently gotten the same issue.

I suspect it's the 12v, the battery is barely kept alive if I don't drive it for +1 day. Getting red triangle during boot up. It's probably 3 years old.

However it first appeared when under the front of the car scrapped on a ramp. And it's been intermittent as well, no fault codes.
Could I have broken an ABS component?

Torque app shows no regen, just friction braking. It's sketchy enough, hard pedal feel, no abs anti lock brakes. Don't want to find out if the stability control has gone too in the middle of autumn...

 

No, if those warning lights are lit up on the dash, then there ARE codes in the braking ecu's. If you are only using Torque, it cannot talk to most of the ecu's on a Gen 2 Prius.

See this thread for reviews of OBD apps and devices.
https://priuschat.com/index.php?threads/232741/

Some can scan all ecu's, others are more limited.

Another option is to use a small length of copper wire to jumper two particular pins in the OBD connector, turn the car on, and count which lights flash how many times. Search for "flash codes" to get details.

Once you have codes, then we can give better advice on how to proceed.

Posted via the PriusChat mobile app.

 

Sounds like a Brake Booster fail. Increasingly common and should be throwing codes. Most likely your power brakes, abs and stability control went with it and you are in failsafe mode with reduced braking.

 

What mr_guy_mann said. Get the trouble codes, using the jumper wire / count blinks method, if you don't have a scan tool that can read them.

With the history of having scraped on a ramp, it's worth finding out what the codes are; could be an oddball situation, this one.

Prius trivia fact for the day: the Gen 2 is the only Prius generation with no booster in the brake system.

 

Thanks everyone. With limited time I managed to get the 12v replaced with a new battery and codes scanned (none of which the Torque App caught).

Regen fault, ACTV brake booster solenoid, and "C" Pressure censor. After 80 miles of driving, the lights haven't disappeared - yet.

 

Thank you very much I'll pursue that. It can still stop thankfully.

 

The C1259 and C1310 are from the brake ECU, only saying "I've heard there are trouble codes in the HV control ECU, go look there."

But this scan tool you are using isn't showing you the HV control ECU codes, which are the ones you really need to know what the story is. A better scan tool should retrieve those. We have a thread reviewing some apps and indicating which will work for that.

For what it's worth, you haven't got even one single code associated with a brake system failure. The regen braking is disabled when the brake system knows there's an HV system code, because it's the HV system that does the regen. That's what's going on.

 

I love looking up old threads like this describing my EXACT problem and never any update or follow up saying what the fix was....off to the next rabbit hole thread for me!

 

Do you mean that your EXACT problem is that your car scraped in a ramp, and you have since read your trouble codes using a scan tool that showed you C1259 and C1310 but will not show you the other codes that those codes mean you need to read? 'cause that's the exact problem in this thread.

Either way, just getting the trouble codes from your car that say what your car's issue is will be the way forward. There are so many possibilities and so many different situations in other people's threads that if you're just skimming a bunch of threads where other people had the same warning lights and their cars acted the same funny, the rabbit holes are of your own making.

 

Sounds like a Brake Booster fail. Increasingly common and should be throwing codes. Most likely your power brakes, abs and stability control went with it and you are in failsafe mode with reduced braking.