Last week at about 7 months & just shy of 10000 miles I get a "Check Pre-Collision System" warning message on the MID on the first start of the day. I power down & restart & the message disappears. Over the week I try to get the PCS to engage while the cruise control is off. Every time I end up braking before the car reacts to the stopped or slowing traffic. The message didn't set a DTC (no surprise) that could be read by the ScanGauge. I told the dealer what happened. Their response was "it didn't set a code" and "system is operating properly". Is there a practical way to determine whether or not the PCS is functioning without playing demolition derby? Thanks for your help. Jim.
Since the system isn't designed to brake until a crash is unavoidable, you're not likely to test the system in any sort of normal driving. I'd say that as long as the message doesn't repeat and there's no warning lights, you're probably fine for the moment. Might've just been a glitch. Since it goes through the same checks every time the car is started, you'll probably get the warning again if it fails... ...but if you really want to test it, there are ways. Some people have tested it by setting up a stack of boxes - just be aware that the car isn't designed to stop before the boxes as some other pre-collision systems are, so don't take that as indication that the system isn't working. Somebody once mentioned that they activated the PCS (well, certain parts of it anyway) by emergency braking on the highway - in other words, switching very quickly from gas to hard on the brakes caused the seat belts to retract, even though there was nothing in front of them. If you can find an empty road with nobody behind you, that would be another way to test some parts of the PCS system.
For your enjoyment [ame=http://www.youtube.com/watch?v=sCzC-ZOk-XQ]YouTube - Pre collision system in 2010 Prius V with ATP[/ame]
I had the alarm once. When I was setting the TPMS I inadvertently turned the PCS off which caused the warning to come on. I assume you have checked the switch? Actually my symptoms were slightly different, with the switch off it just went into alarm whenever I was in Ready and stayed that way.
