Experienced a scary PCS false trigger...
09-02-18, 08:22 PM
#1
Lexus Fanatic
Thread Starter
Experienced a scary PCS false trigger...
So, yesterday I was on my way up to see my cousin in WV in my LS460L equipped with radar cruise and the Pre Collision System (PCS). Theres a section of highway at the interchange of I-70 to I-81 where they are doing a ton of construction, its pretty rough and the road heaves and transitions from asphalt to concrete and back again.
Well...something must have tricked my PCS into thinking I was about to hit something (Nothing was remotely close), and the car slammed on the brakes at about 50 MPH, tightened the seat belt, beeped and flashed at me. Luckily, nobody was behind me...
Our 14 Jeep Grand Cherokee had PCS and did that to me once, but it was on a residential street not a highway.
Years ago a member in the 4GS forum had that happen when I had my 4GS, and he immediately traded it in on an LS without that feature. I can sort of understand why LOL
I'm not worried about it, sure it was a fluke but just thought I would share.
Well...something must have tricked my PCS into thinking I was about to hit something (Nothing was remotely close), and the car slammed on the brakes at about 50 MPH, tightened the seat belt, beeped and flashed at me. Luckily, nobody was behind me...
Our 14 Jeep Grand Cherokee had PCS and did that to me once, but it was on a residential street not a highway.
Years ago a member in the 4GS forum had that happen when I had my 4GS, and he immediately traded it in on an LS without that feature. I can sort of understand why LOL
I'm not worried about it, sure it was a fluke but just thought I would share.
09-02-18, 08:33 PM
#3
Lead Lap
Not a fluke, on one of the backroads I take to Annapolis there is a small bridge with a little transition and I mentioned to my service advisor that my old LS600 would tighten up the seatbelts (it had regular PCS so no braking) sometimes near that bridge and scare the crap out of me. He told me one of his customers bought a new 13 LS with advanced PCS and his car would react the same way as yours did (tightening seatbelts and braking) over the same transition and he complained that it could cause an accident if someone was behind him. A tech took it out to the same place and it happened to him as well so the dealer bought the car back and ordered him a new one without advanced PCS.
09-02-18, 08:38 PM
#5
Lexus Fanatic
Thread Starter
I think it was the transition of roadway surfaces in rapid succession from dark to light to dark to light...
Whereabouts in Annapolis Pat? Maybe I'll give that a try next time I'm out there...
Cant turn it off in the Lexus.
Whereabouts in Annapolis Pat? Maybe I'll give that a try next time I'm out there...
Cant turn it off in the Lexus.
09-02-18, 08:49 PM
#7
Lexus Fanatic
iTrader: (20)
My jeep could definitely get confused now and then and in general braked sometimes with radar cruise when it didn't need to. My genesis g90 seems way more sophisticated and hasn't done anything odd at all yet.
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09-02-18, 08:50 PM
#8
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I have already turned my PCS on my Benz to "late" reaction but I still get false brakes hear and there. In fact, it happened to me two weeks ago. There is this stretch of road where you drive 40-45mph and the road dips downhill and then uphill. At the top of the slight hill, there are two large reflector style "No Left Turn" road signs and some other sign. Im pretty sure that is what triggered the auto braking but it scared me and my passenger *****less. That is one of the only times it has happened without another car in front of me.
09-02-18, 08:57 PM
#9
Lexus Fanatic
iTrader: (20)
09-02-18, 08:57 PM
#10
Lexus Fanatic
There are a lot of deer in that area. Not likely, but perhaps (?) one was in range of the PCS and you simply didn't see it.....though I'll take your word that you yourself didn't see anything like that, and probably would have noticed the one was there. Patgrim's story, however, about the bridge-abutment near Annapolis is interesting.
Anyhow, that is one reason why I ordered my Lacrosse without that system....I've never trusted it. (I'm with Och on that one)
Anyhow, that is one reason why I ordered my Lacrosse without that system....I've never trusted it. (I'm with Och on that one)
Last edited by mmarshall; 09-02-18 at 09:15 PM.
09-02-18, 08:58 PM
#11
Lead Lap
09-02-18, 08:59 PM
#12
Lexus Fanatic
Thread Starter
I have already turned my PCS on my Benz to "late" reaction but I still get false brakes hear and there. In fact, it happened to me two weeks ago. There is this stretch of road where you drive 40-45mph and the road dips downhill and then uphill. At the top of the slight hill, there are two large reflector style "No Left Turn" road signs and some other sign. Im pretty sure that is what triggered the auto braking but it scared me and my passenger *****less. That is one of the only times it has happened without another car in front of me.
LOL, no. Had there been a deer in front of me I'd have seen it. It was broad daylight.
09-02-18, 09:24 PM
#13
Lexus Fanatic
Not a fluke, on one of the backroads I take to Annapolis there is a small bridge with a little transition and I mentioned to my service advisor that my old LS600 would tighten up the seatbelts (it had regular PCS so no braking) sometimes near that bridge and scare the crap out of me. He told me one of his customers bought a new 13 LS with advanced PCS and his car would react the same way as yours did (tightening seatbelts and braking) over the same transition and he complained that it could cause an accident if someone was behind him. A tech took it out to the same place and it happened to him as well so the dealer bought the car back and ordered him a new one without advanced PCS.
The road is Rt. 450 between Crofton and Annapolis mall. Since the guy that had the LS lived off of that road and traveled daily on it the dealer or Lexus bought it back.
The road is Rt. 450 between Crofton and Annapolis mall. Since the guy that had the LS lived off of that road and traveled daily on it the dealer or Lexus bought it back.
https://www.google.com/maps/@38.9860...7i13312!8i6656
09-02-18, 09:31 PM
#14
Lead Lap
Is this the bridge you are talking about? It crosses the South River on 450 between Crofton and Annapolis. And, as you say, it goes from dark asphalt to light concrete.
https://www.google.com/maps/@38.9860...7i13312!8i6656
https://www.google.com/maps/@38.9860...7i13312!8i6656
09-03-18, 12:37 AM
#15
Lexus Test Driver
My car does not have any of the above features, but the IS300 loaner I had last month did and I didn't care for it one bit. There are too many times when making a turn one has to cross over a painted lane line, and then suddenly the steering wheel has a mind of it's own and becomes hard to turn. This can be a hazard when trying to make a faster maneuver, but thankfully I didn't have that come up. I am hoping my next Lexus will have a way to permanently shut off all these nannies. A smart and alert driver can do more good on his/her own, vs. the chances of one of these nannies getting in the way and causing an accident.
Has any studied surfaced showing the rate or % of accidents caused by these? I am sure it does it's share of saving people who are not paying attention, but that aint me and I don't want to carry the burden of irresponsible driver's bad habits.
Has any studied surfaced showing the rate or % of accidents caused by these? I am sure it does it's share of saving people who are not paying attention, but that aint me and I don't want to carry the burden of irresponsible driver's bad habits.