Major Problem with 2010 Prius PCS

Granted I don't own a Prius, or a Prius V, but my understanding was that the PCS warned you first by beeping before starting to apply and offering extra braking force. My understanding is that it slows...but never "slams on the brakes" for you.

I would also offer that if you are driving 45mph and heading towards a 4x8 sheet of steel that perhaps your Prius is reacting correctly...you should slow down.

 

I hope he is brining his pocket metallurgy test kit along to test the plates, because that doesn't happen here on the west coast...

 

nice firts post ;-)

 

If you'd like to verify that it is or isn't the PCS, you could always disable the PCS by pressing the PCS disable button under the drivers side dash (looking at the steering WHEEL head-on, and in-line with the steering column, it's the button on the left...I think, the other button right beside it is the TPMS Initialazation button, the V has two buttons).

This would at least allow you to determine if it is the PCS that's setting it off.

David (aka Blind Guy)

 

I hope those steel plates are level enough with the road surface to be safely driven over at 55 mph. Hit it at the wrong angle and the airbag will deploy (that's how my last car was totaled, except it was a raised manhole where someone had moved the barricade on an unpaved road under construction).

 

We have a 5 and drove cross country with it. Went over plenty of metal plates and dirt roads. The only time the brakes came on by themselves was when a deer jumped out in front of us. Sure glad it did as I could not have reacted fast enough.

To me it sounds like a defect in your specific car which your dealer should fix.

Stan Ames

 

I can only recall one time when my seat belts tightened up in my Pirus V, but it was when I had to slam on the brakes for some reason or another. Who knows if the car was assisting me in pushing the brakes or not.. I just noticed it was gearing up for a crash by tighting the belts. lol It's never randomly slammed on the brakes on me.

Compared to the laser cruise my Infiniti had, this Prius radar cruise works a little better and even works in direct sunlight and rain. It doesn't even slam on the brakes when someone pulls in front of you like the Infiniti did. It just slowly eases off the accelerator to regain proper distance only using brakes as a last resort. I use it all the time and am very happy with the results. It's one of the things Toyota did right on the car.

 

Crikey! It must have been one of them cybernetic deers the future...

 

When Bambi crossed my path the car didn't respond. Didn't see it until it was in front of the headlight. Fortunately for both of us the little bugger was fast enough to escape without injury. If you are running over raised steel plates better increase the tp.

 

This confirms my feeling again that the Prius should be considered a "Technically Advanced Vehicle" not unlike the FAA's (perhaps late) designation of Technically Advanced Aircraft and that as such, the operators should be expected to be thoroughly familiar with the system just as pilots are required to understand how their aircraft systems work and/or require such training.

From these posts, I gather that few have read/understood the manual when they describe the pre-collision warning system in detail. As I do not (yet) own a Prius, the best I have is recollection from reading it at the dealers (but I recall a separate post detailing the system operation).

The PCS has 3 components, only ONE of which can be disabled via the switch. This optional component is the one that sounds alarms and prepares the brakes for activation. The conditions of activation I believe was vehicle over 9mph and closing rate >9mph.

Then there are the two other systems, one better termed collision mitigation as it employs the brakes automatically and seat belts pre-tensioning when the system decides a collision is unavoidable (I believe "imminent" was the word they used) and tries to simply reduce the collision speed, not necessarily avoid one. This system cannot be disabled by the user (at least no indications in the manual).

Finally, the third part is only active with radar cruise control (I forget the parameters) but it will also automatically apply brakes when closing rate too fast.

These 2 options (excluding the visual/audible warning), do NOT emit any warnings as they are designed to engage only when a collision is near certain.

The experience the OP describes sounds much more like the system perceiving an imminent threat beyond the point of the warning system and only activating the emergency stop actions. Thus, disabling the PCS with the button and the lack of audible warnings does not mean that PCS did not engage (in this case, erroneously).

I'm very glad to hear of this report, as this was one of the greatest fears I had in the PCS was the rate of "false alarms". I had posted earlier with a query about people's experience with the PCS, and it sounds like this is an unusual, exceptional case, and I agree with many others like a calibration or other adjustment is probably in order or the situation is extremely unique (and unlikely due to the the metal plates alone).

 

I think the tech is correct, the radar antenna probably needs to be aligned and the system needs to be tested. As others have said it's not working normally. Yours is the first post reporting this problem so be sure to keep us updated on what they find. Thanks.

 

troll spray

To my knowledge and experience, which is admittedly minimal with the Prius V, the PCS will never "slam on the brakes". I've never heard of a state using steel plates on a 55MPH plus roadway.

Troll harder.

 

I've never had this problem with mine.