PCS Warning light on!

Get Mini VCI so that you can retrieve the logged diagnostic trouble codes.

 

Just for the challenged: what is PCS again?

Googled: Pre Collision System

 

The PCS light will turn on if you turn PCS off. Under the dash close to the steering wheel shaft there are two buttons. One is the TPMS reset/set button. The other is PCS on/off. Both buttons are labeled. I have been running since day one with PCS off. PCS light is on.

 

@David Beale: why do you turn it off? Is it buggy?

 

Sorry, using a phone, harder to quote. David's saying he keeps PCS turned off.

 

The button is on the bottom of the dash, over your thighs. There are two, as I posted earlier. Put your head on the floor and look up. It's in the owners manual.

PCS is related to the "radar cruise control". It uses the "radar" unit.
I keep PCS turned off because, if you read the owners manual, it warns the system could detect a bridge expansion joint as a stopped vehicle and apply the brakes, as prep. for a collision. What, do you suppose, would happen at rush hour, driving at speed, on a bridge, if you suddenly, WITH NO WARNING, applied the brakes? The system is dangerous, not needed, and generally poorly thought out. I leave the O-N/ O-F-F switch in the O-F-F position.

I DO use "radar cruise control", even in the city. It works fairly well, but does sometimes detect vehicles in the next lane and will slow for no reason. Of course, it can't anticipate like the nut behind the wheel. It reacts -conservatively-, a good thing I guess, to the point of slowing even when a vehicle has moved to a turnoff lane and is slowing. Easy to over-ride with the throttle, but irritating.

 

Mine is caused by scangauge and extreme heat. The only time my PCS warning lights come on is during hot summer. Regen is lost when warning lights come on. I can reset the lights by rebooting. Full blasting the AC also help prevent the warning lights.

 

In almost 100,000 miles I experienced only one "false activation" that lasted for an instant. I don't know if it braked or just disengaged the cruise control. It certainly didn't slow the car significantly.

I agree that PCS is conservative. Instead of gradual braking earlier it will brake harder later. I always intervene.

 

How do you reset the PCs system, my light has been on for 4 months I tried disconnecting the battery and the light is still on. I tried cleaning the sensor in behind the Prius badge and nothing

 

Near the beginning of this thread I posted the location of the switch that turns PCS on and off. The light will come on when it's off. Under the dash, near the steering wheel, you should find a push button switch. You have to put your head on the floor and look up to see it. As I recall, it's labled "PCS".

 

Thank you guys for having this here. Pushed the PCS button under the steering column to right of OBD II port made my PCS light go out (PCS System come on) I am so relieved my dumb mistake only took out 1 fuse.

2010 Prius Adv Tech with PCS here. You have fixed my very expense mistake, or the last part of it. I broke my Prius dead while Jumping the contacts in the engine fuse box. For years I thought the protected black terminal was ground, and never questioned why a ground comes from or to a fuse box. That blew the 100 Amp fuse underneath the fuse box (have yet to learn how to replace it). At that point the 2010 Prius was dead and immobilized. Two tows $120 ( to Toyota Service for $140 and to home) came up with no solution just lots of money. Next learned of a guru Prius guy in SLC, he patched it and had it running the day he looked it over. Only this PCS light was on and knowledge jumping/bypassing this 100Amp fuse should be resolved ASAP.

 

can you clarify "he patched it"? software?