Pre-collision system activation

Great post! Thank you for providing a thorough statement of what happened.

While your explanation seems to be the most plausible one aside from a malfunction or default, I would not accept it as the answer.

Please call your dealer immediately, as well as Toyota Customer Care. This does not sound right. The danger to you and others seems rather excessive.

By the way, I did not quite follow or understand your plan to see if the PCS activates after you have turned it off. Did you mean to suggest something different, or are you concerned that the switch may not actually disengage the system?

 

I forgot to mention that I've seen some fairly intense fog on the GG Bridge. Here is a picture I took on what I thought was a fairly typical morning in San Francisco:

 

Looks like the PCS radar got a strong reflection from the bridge metal expansion joint two cars ahead of the Civic. Then the reflection went away in just a second, the PCS then understand the obstacle disappeared and resets itself.
You may want to drive on the same lane again and see if this happens again.

 

I am driving a Toyota demo Prius 3G car for some weeks now, and last saturdary I drove through intense fog with radar on maximum range with no problems at all.

In fact this was one aspect of the ACC I immediately commented on Prius-PT.com site. It was the first time I was driving in dense fog without any fear of rear ending someone else. Fantastic.

The Prius would "find" the next car and start braking far sooner that i would, since it started with no car in clear site at all. Again, this is a major safety feature that needs to be mentioned when discussing ACC.

The false positive you got was probably due to the slope and dilatation joint as others have mentioned.

 

I agree with this as the cause.
The radar would be passing through the tar/concrete & reflecting off the metal.
I honestly reckon this will happen everytime you drive this stretch of road/bridge.

I wonder what the long term solution will be.
The only thing I can think of is somehow the camera used for lane keep assist 'analyses' the relative height of the road marking (dashes) to the metal or whatever is on the road ahead.

Good luck Toyota!!

 

It would be really bad if this happened while there was someone following very closely.

 

This is the most likely explanation. To the radar, it would look like you were driving straight toward a metal wall.

Tom

 

Interesting to hear, I've always wondered what it was like when it activates, but dont have the nerve to try to trigger it. Just for clarification, PCS is disabled when the light is displayed on the dash? or if there is no PCS light on the dash is it disabled? I know its in the manual, but I dont like to RTFM.

Nate

 

The PCS light will be "ON" when the PCS is disabled.

 

If you disable PCS, the PCS light appears. Enable it again, it goes away.

 

I know this is an old post, but I wanted to share my experience with the PCS this evening. I was headed out to dinner, and a van that was slightly in front of me and to the right came to a stop. This just happened to be in a place where his lane was ending, so I went to the left to go around him. As I got a little closer, the PCS activated and slammed on the brake. It scared the crap out of me. I'm sure it was because the car saw the van as being in my path, even though it actually wasn't.

As with the original post, luckily I wasn't being followed by anyway, so no one hit me. I will be a lot more attentive to potential PCS activation scenarios going forward.

 

Has anyone on here been saved from a crash by the PCS?

 

I think that if you had slowed down along with avoiding the van, then PCS would not have activated...you must have closed on the van pretty fast (possibly without even braking) and the PCS reacted.

 

I had PCS invoked once on the freeway when a car started to merge towards me from the onramp and I got on the brakes very quickly. Neither I nor the car slammed on the brakes though; just cinched up the belts and probably did some prep for a brake slam. Since it was a bunch of priuschatters in the car with me, they all enjoyed the demo a lot!

 

I don't think the radar reacts to light reflection. It should only be sensative to physical objects. PCS responds to objects very close to the car.

 

Yes, just last Friday, it saved me from serious injuries. I was driving about 30 miles/hour in a major street in DC under day light. There was no traffic lights, stop sign, nor other cars in front of me. But all of a sudden, a van making illegal left turn (or U-turn) appeared in front of my nose from my left. The next thing I knew was the flashing warning light, tightend belt, and "Ban", I hit directly into the van's passenger door. Two of the airbags exploded (one on the steering wheel, other under my knees). My car suffered substantial damage in front and not drivable. Fortunately no one was injured in this accident. The van driver got a ticket from police, who happen to be there.

I was very lucky indeed to have the PCS. I did not even touch the airbags, just saw one exploded on the steering wheel a foot from my face. I am sure if the belt did not tighten, my body would lean forward to hit the airbag. It could harm my face as many people reported. As I said, I did not have time to react to the van, so I did not conciously hit the brakes. But the PCS might have applied brakes for me. I couldn't verify it. However, I guess the damages to the front end of the care would have been greater if there was no braking at all.

The other driver's insurance is going to pay for the damage. But I am very sad for my one-year old Prius V. I hope they will be able to fix it to pre-accident condition instead totaling it. I will hear from the insurance adjustor Thursday. Wish me good luck!