Prime Stall Shut Down

I’ve had that happen while on the highway. All my electronics “rebooted” but I didn’t lose power. I wasn’t on cruise control so maybe I just didn’t think that much about it. If I was on cruise control I would probably think the car lost power. I believe your normal reaction would be to take your foot off the gas.

Probably the 12V PDU rebooted which kills all lights, accessories and creature comforts. A lot different than the Inverter which controls the drive train.

Unsupervised!

 

A thread over in the Maint and Troubleshooting Forum.
Prime Shutdown | PriusChat0
Nevermind that's just you crossposting.

 

you'll have to define it. the reboot is not normal but common. it is not unsafe. loss of motive power, even for s few seconds is a whole nuther can o worms.

 

So now we have to deal with Windows OS in a Prius?

 

that's good news, please make details available when you have them, for others. hopefully a recall coming

 

Happened to me tonight All system shutdown! Message flashed “Engine Malfunction, visit dealership”, followed immediately by “ Brake Failure”, and all cautionary LEDs lighted up. The car behind me narrowly missed me. The stall took the power steering out as well, although I had electricals....AAA tow dropped wife and I home and took the car to Stevens Creek Toyota, San Jose. The car has 5000 miles.
I missed a couple of close calls albeit I was on the shoulder...very disappointed. Will file with NHTSA. Unsafe at any charge!

 

Umm. Wait, what? How is that even possible? Is that a serious design flaw or is this bogus? If brakes can really malfunction due to a software issue then isn't this whole issue going to turn into a major $h1t-show?

 

I had a “engine failed to start” MIL indicator on my Gen 2 and it was fixed with a firmware update. Hopefully it’s that simple in this case.

 

One case involving a Camry during the sudden acceleration issue may have been due to the brake software. An expert called it 'spaghetti code', and didn't follow best practices.

In this case, the brake failure warning may simply have triggered from the loss of engine power. All the other warnings lit up too.

 

Affirmative... wife can vouch for it. Hence waited 55 minutes for two at night. Stevens Creek Toyota, San Jose, most U.N. cooperative. Filing complaint with National Safety folks. I am in the Quality and Cimpiance field but in the multiple message, and alarm tones did not do a screen shot of brake malfunction...was commanded to use “P Brake Mafinction”. ... dealership refused liner... so will use their rental and claim through, hopefully but looks like legal action... need guidance from you all. Toyota is new to me. Thanks

 

Car stalled! No forward motion.., engine had no power although electricals were okay...

 

I sure appreciate all the feedback.... dealership ( in fact I am still there) said wire harness got chewed up by rodents (hmmm my S Class and wife’s XC 90 share the same garage). Hence total system failure and disengage brake and all functional commands!

Don’t buy it 100% and even so SPF (single point failure) is poor design. MBZs go into fail safe limp home mode. Oh well filed an insurance claim...never Toyota again!’

 

So mice chewed wiring, which caused multiple system errors, probably made brakes and steering heavy (but still operable). Emotions aside, what do you expect Toyota - or any car manufacturer, - to do, have redundant lines for everything, like in airplanes? Offer free rodent control to every owner?

 

toyota wiring is soy based, mice love it

 

From @Azmat Siddiqi's report, it’s not clear to me that there was a failure of actual braking, or just a (quite distressing) loss of power, followed by brake-related warning lights and error messages. If it was the latter, as @Trollbait kindly suggested, the electronically controlled brake system may have been working as designed.

As many readers know, Toyota’s hybrid system achieves good fuel economy, in part, by allowing the car to substitute regenerative braking for hydraulic (friction) braking, using Motor Generator No. 2 in the transaxle as a generator to simultaneously slow the car and recharge the HV battery. Toyota could have provided a separate control for this, as with dynamic braking on a locomotive, which is operated with the throttle or a dedicated lever. For a mass-market car, though, Toyota needed to keep the traditional driving interface.

This would have been difficult to do without allowing the control software, under appropriate conditions, to override the hydraulic braking behavior when the driver presses the brake pedal. (Such an override is also needed for the anti-lock brake system, but that’s another subject; see Toyota’s ABS video.)

Toyota calls this Regenerative Braking Cooperative Control, and in the New Car Features book (more info), they explain how it works:

“During braking, the skid control ECU calculates the required regenerative braking force and transmits it to the hybrid vehicle control ECU. Upon receiving this signal, the hybrid vehicle control ECU transmits the actual regenerative braking control value to the skid control ECU. Based on this result, the skid control ECU calculates and executes the required hydraulic braking force.”​

(The skid control ECU is the computer that runs the brake system.)

If the skid control ECU receives a malfunction signal from the hybrid vehicle control ECU, or if it loses communication entirely, it’s designed to fail safe and rely only on hydraulic braking, but it will also store a diagnostic trouble code, such as C1259 (“HV Control System Regenerative Malfunction”), C1310 (“HV System Malfunction”), or U0293 (“Lost Communication with Hybrid Vehicle Control System”), turn on warning lights, and display error messages on the combination meter.

None of this excuses the initial failure, of course, but it’s one possible explanation for part of what happened.

As for rodent damage to wiring, it sounds plausible to me, though the class-action lawsuit over soy-based insulation was dismissed last year. Toyota does provide redundancy on critical circuits, such as those to the accelerator pedal, but keep in mind that, like all too many PriusChat members, mice don’t read the Electrical Wiring Diagram, so they may eat more than one wire in each circuit.