gsarff

I picked up my 2014 F-sport ultrawhite CT200h a little while ago, I got the radar cruise control and
the PCS warning system. I noticed an inconsistency in the manual, the text and the diagrams of
the button saying the system is enabled and disabled are not in sync with the pictures in the
manual and what the car actually does. I cannot get the dealer to figure this out and so I thought
I would ask here. I have read there are relatively few CT's with radar cruise and PCS, so the
audience is limited, but maybe someone might own another lexus with it too and so I thought
I would ask. The manual says this:

It has a clear picture of a button under the dash with a red arrow pointing in, labeled PCS OFF
and then it has numbered pictures of the button from the side labeled 1 and 2 saying 1 saying
PCS breaking is disabled, and 2 is PCS breaking enabled. Then the text says the PCS light
in the instrument cluster comes ON when the system is disabled. That should be when the
button is pushed in, according to the diagram. However on my CT the light comes on with the
button pushed OUT, not IN. The dealer service manager pushed it in, and said it was on.
yesterday I had about 1/2 a second before I came to an abrupt stop by my pushing on the brakes
during a stop on a major avenue due to traffic jam with a broken intersection light.. My fault, I
glanced away for just a moment, totally my fault. But the PCS didn't do anything and I thought it
would have by then, I was within about 10 feet of bumping the car in front of me, going maybe 10
mph. The lexus technology person who works at my dealer said her IS reacted with all the
warning tones and lights when someone pulled out in front of her on a street she was driving,
so I have heard what it is supposed to do. My question is, I guess, is the manual correct, or
incorrect about which is ON and which is OFF, since it is a feature on the car, I want to make
use of it, and have it on, but the manual is inconsistent and the dealer thinks one thing and I think
another. Any ideas? Can anyone read the Lexus engineer's minds, in which way such things
work on a lexus?
Thanks very much, I know this was a long post, I just wanted to be thorough. My car behaves
the exact opposite of the diagram below. The PCS light comes on when the button is OUT
not IN which the picture says is DISABLED.

RXSF

If there is a PCS light on your dash, it means it is off. There should be no light, that means its on.

I am not sure if the Lexus PCS works at such low speeds

gsarff

Thank you for the reply. I guess the button labeling in the diagram is a typo by the documentation people.
I will not touch the button again.

jhs82

10 mph is too slow. You'd have to get really close for it to brake, if it ever would brake at that speed.

lexusrus

I know I am replying to a post dated May 2014.

I don't know about the PCS on the CT200h. But I have PCS (very rare option) on my brand new 2013 LX570 (bought it last year 2013). My LX570 with PCS engaged, will only brake at highway speeds and then somewhere below a certain threshold (like 25 mph or so), it will not brake any more. While the PCS is doing "its thing" alarms will go off and you will hear the beeps and all that. Also the center LCD display directly in front of the driver will have a little picture with the LX570 with red brake lights flashing.

But one thing for sure, the PCS (at least on my LX570) WILL NOT bring the vehicle to a complete stop. The driver must physically and manually step on the brake to bring the vehicle to a complete stop. I wish this PCs system will bring the LX570 to a complete stop, but it will not. The ability to come to a complete stop in slow city traffic to me is the key to avoid most rear end accidents.

This PCS system is different versus some of the other manufacturer's "PCS system" where the vehicle will come to a complete stop (like the Volvo's, after Volvo fixed its initial bugs). There are good youtube videos on the fiascos during Volvo's initial test with invited journalists where the test Volvo vehicle slammed into the back of a flatbed semi-trailer without stopping at all. Volvo had since fixed this. There are other youtube videos on Top Gear comparing various "PCS" systems from the low to the high end. Surprisingly the S class MB did the worst as I recall.

Raidin

In the manual, on page 262 of the 2014 model, it states that the PCS system will not intervene with braking unless you are at least over 10 mph and have over a 10 mph difference in speed between you and the car in front of you. There are a few other requirements listed for the various parts of the PCS system (warning, seatbelts, braking stages).

My 2014 F Sport has PCS and it works all the time during normal driving with my radar cruise, but it rarely fires up outside of those situations. If I am traveling on the highway and start changing lanes, making 2 lane changes in succession, while having a much slower moving vehicle in the first lane I am changing to, the system warns me as I pass behind it.

The system is designed almost purely as a warning system, not prevention. Only in extreme situations, where a collision is nearly or completely unavoidable, will the system "mitigate" damage by applying more brake pressure when you finally hit the brakes OR start braking for you, but not enough to stop the car in time. It's all about lessening the damage.

Also, the manual does state that if you see the PCS light on your dash, then it's a warning light that the system is current OFF.

spwolf

PCS is collision mitigation/warning system.. so you should not experience it unless you are in crash.

Some cars have city brake systems that autobrake at lower city speeds (up to 37mph I think). Interestingly enough, Subaru has the best system out there currently:
http://www.iihs.org/iihs/news/deskto...ash-prevention

I think first Lexus with autobrake under 37mph is going to be Lexus NX... they plan to introduce the system to all of their vehicles by 2017 - both Toyota and Lexus.

Of course, keep in mind that autobrake system make a lot more mistakes than PCS systems do... there were few complains in Europe with these systems where they did a full stop when not needed and accidents almost happened due to that.

gsarff

Thanks to Lexusrus, spwolf and Raidin, (if my memory is right on the last name, sorry), I recently
took a long drive, 1588 miles one way from Salt Lake City to central Illinois to visit family and I
finally had first hand experience of the PCS system going off in the car, when someone slipped
in between me and the car in front of me while changing lanes to get off the freeway with no
signal. The PCS went off with several beeps and the radar cruise control slowed my car way
down too, so in combination it did what it was supposed to do, the PCS warned me. This was
in a construction zone where the speed limit was 50, I had never had this happen before, but it
was interesting to see. I did step on the brakes immediately, some people just cannot leave
a gap between two cars alone, it is like an invitation to them to get in the middle, sigh
But I am glad to know it works. A friend of mine bought a volvo in Europe, in the netherlands and
was telling me about their city-safe system, which supposedly brings the car to a complete stop
at 35 mph and below. Sounds nice if it works. I heard on the radio that Salt Lake City was 6th
most dangerous city to drive in based upon wrecks and fatalities , and I can believe it, when I got
back home from the open road I had to curb my constant cursing at other drivers, and right on the
way to my house from the 1588 mile trip, I saw a near accident right in front of me, I was the first
car in front sitting at a light and my direction had a green arrow and as cars were turning another
car entered the intersection from the west and nearly T-boned one of the cars, then slammed on
brakes and backed up into cars coming to a stop in their lane behind them , because they were
out in the middle of the intersection. Some stupidity there all around. Even if the PCS does not
work in town here with the low speed limits, it is nice to know it is there, after my long drive on
I-80 and what nearly happened to me. Thanks to all the posters who responded.

Raidin

Just glad you're ok. =)