RunAway Prius 2001 - Sorta Interesting

That sounds like a genuine problem. Good thing you didnt flip your car when you turned it off.

 

Interesting and a first report that I'm aware of. Welcome to the 'bleeding edge.'

Bob Wilson

 

Hi TexomaEV,

Does your surge in speed feels like when you shift from [D] to [N]?

Does your engine rev up feels like you are in mode but without regen?

If it does, you may be experiencing the same problem that I reported here:

http://priuschat.com/forums/international-owners/6539-prius-in-singapore-2.html

Have you use the SGII to read out all the modules voltages and resistances?

 

Actually Vincent1449p had this excellent post:
http://priuschat.com/forums/international-owners/6539-prius-in-singapore-2.html#post1069605

Very clever diagnosis and fix.

Bob Wilson

 

this reminds me of when my hv battery went bad on my 01 prius, i wouldnt call it surging but it sure felt like it, it felt as if the engine downshifted to a lower gear and throttle response was completely different, i havent been in this fault condition long enough to determine if there would be a surge problem as described.

 

During fail-safe modes, engine RPM may increase independently of vehicle speed, and regen may be disabled. However, the vehicle will stop if the brakes are applied.

 

While the Gen 1 Prius can function quite differently when operating in a fail-safe or limp-home mode, most folks will seek service rather quickly in such a situation, rather than drive the vehicle for hundreds of miles after warning lights have illuminated. Your situation is more of an operator issue than a vehicle design issue.

 

I completely agree with you, since you couldnt provide a reason for the OPs condition it must be operator issue.

 

That is true, but the above statement does not establish whether or not Toyota is at fault.

Why on earth would you take offense? According to you, this vehicle had a faulty HV battery, which resulted in a P3006 code. This can be expected to cause the Master Warning light to illuminate. The owner's manual states that when this happens, one should "stop your vehicle in a safe place immediately."

However, you chose not to do that, or to repair the issue prior to operating the vehicle, but to take a seven hundred mile trip.

At some point, the brake warning light came on. This usually indicates a problem with the brake system, whether the vehicle is a hybrid or not; indeed, Toyota recommends that you "depress the brake pedal firmly and bring the vehicle to an immediate stop." It has been my experience that most vehicle operators will stop the vehicle and seek help if a brake warning light comes on.

But you kept driving. Not surprisingly, you found that the vehicle was not operating properly, and in particular, was not stopping properly. From this experience, you have concluded that you have stumbled upon a "runaway Prius" issue and that you have "PROOF that there is a safety issue."

Strong words. One would assume that someone of such an opinion would at last stop operating their vehicle immediately, as Toyota had suggested. But no, you continued to experiment with the "runaway event", presumably on public roads.

I have no issue with your decision to experiment with the vehicle in such a compromised situation. I do, however, take issue with your suggestion that the problem is somehow Toyota's fault. If you had operated the vehicle as suggested in the owner's manual, you wouldn't have had the problem you have described.

Follow the instructions in the owner's manual, and you'll be fine. Experiment with the vehicle after the manufacturer has told you not to do so, and you do so at your own risk as well as the risk to those who share the streets with you.

You're not a victim. You're a volunteer.

 

I didn't say I couldn't provide a reason for the OP's condition. Neither did anyone else. If the OP wants to know, I'll be glad to explain the issue. It's nothing new.

But please keep in mind that folks who ignore multiple warning lights while driving generally end up having "adventures", regardless of the type of vehicle they drive.

 

You're describing a niche in the control laws and I appreciate the 'heads up.' I'm not sure we can make any practical use of it. As for Toyota, I would surprised by any other action other than changing the control laws than to convert "limp home" into "must tow" mode. Which could be worse.

Bob Wilson

 

That's not entirely true. While the HV battery may have been the root cause of the issue, the system will often inhibit regenerative braking so as to avoid charging a defective battery pack. When this happens, the brake warning light illuminates to indicate a compromised braking system, as yours did before your "issue" arose. You chose to ignore that warning.

You had to drive your vehicle for hundreds of miles with multiple warning lights to discover those "certain conditions". Again, the manual says to stop the vehicle when warning lights illuminate. This is not something unique to the Prius, or to hybrids.

And according to your first post, the vehicle did not exhibit this behavior at first. You had noted that it

I think it's safe to say that the vast majority of drivers would have their cars looked at if multiple warning lights came on and the drivetrain shut down. In this case, you even knew what codes had set. It's fair to say that you had strong indications that something was wrong, no?

I'd also like to point out something else. In the rare instance that the problem is intermittent, and the issue doesn't return within the next few key cycles, the system will reset. However, you chose to defeat this strategy by either clearing codes or turning the vehicle on and off several times in rapid succession, something that is often recommended on this forum as a "fix", even though it fixes nothing. Most drivers wouldn't have done that.

I didn't say that I thought every Gen I was still owned by the original owner, and I'm not sure why you would suggest that. The vehicles are seven to ten years old; common sense would dictate that most of them are not with the original owners.

Again, most folks tend to wonder if something's wrong with their car when the dash lights up like a Christmas tree. They don't need a manual or special training to tell them that.

You have to abuse the vehicle to get it to do that. Your posts have documented that.

Toyota already knows what occurs. They designed the fail-safe modes into the vehicle. In the rare case that someone will continue to drive such a vehicle for an extended period of time, the system may set an additional code.

Thousands of Gen I Prius vehicles are on their second battery, yet I have never heard an owner complain of a runaway vehicle. Rather, they sought service fairly quickly once a warning light indicated a problem with their vehicle. In some cases, the vehicle's power output was diminished; in other cases, the vehicle drove normally.

If you were driving a vehicle, and the oil pressure light came on, what would you do, and why?