Cruise control in the rain.

At first, I just want to see if the radar of the Dynamic Radar Cruise Control will work in the rain. So one day while it was raining rather hard, I switched on the cruise control and noticed that the auto ranging worked but for a few seconds then the cruise control symbol turned from green to orange and the E2 error came on! I tried that a few more times with the same results. Then I remember reading somewhere that you should not use the cruise control in the rain because it may cause the “hydroplane” effect because the system can not differentiate between the dry and wet road but simply try to keep the constant speed.





At this point, I thought my Prius v (lowercase v for the Pirius v wagon) technicians had thought about this and somehow came up with something that stops the cruise control to work in the rain. My first thought was the rain sensor which I saw in some European cars which activates the wiper when it rains. At that time I misplaced my manual so I could not look up the E2 error message. However, I don’t recall seeing any rain sensor when I worked with my car before.
On the next day, there was no rain but I thought I had an idea so I went out for the test looking for the “key” feature that prevents the use of the cruise control. Yes, it’s the windshield wiper but it has to be on HIGH only.
A few days later, I found my manual so I looked up the E2 error and it says, “ the radar cruise control system is unable to judge vehicle-to-vehicle distance.” And to correct this,” If the windshield wipers are on, turn them off or set it to either intermittent or slow mode.”

 

Thanks! And I want to let you know that I keep my PCS (Pre-Collision System) ON at all time and it warned (beep first, then if I do nothing it will slow down but not fully stop) me a few times already when someone suddenly cut into my lane. Anyway, the system that utilizes radar detection may give you the false alarm when you are driving along the curve where there are either tall medians or sound barrier walls and such. This is because the radar will read "directly" as a straight line in front of you, so if the signal hit the curve wall it may bounce back and think that it's another vehicle in front of you. This is not a bad thing but it's not perfect.