Prius Adaptive Cruise Control Acting Weird

My top spec 3rd Gen prius Adaptive/ Dynamic/ Radar cruise control is acting weird for a while now (it was like that since I bought it). As far as the instrument panel and indicative light etc goes, everything looks fine. When I switch on the cruise control it says 'radar ready' and I can adjust the distance etc using the button on the steering wheel. But good story ends just there. It doesn't actually detect or work as it should. When I set the speed, it would work as normal cruise control would (maintain the speed at a set speed, braking and accelerating as necessary). Being radar cruise control, it is supposed to detect the cars at front and should reduce speed accordingly but my car wouldn't do that. I thought may be the front car is too far, but couple of time I tried getting the car way too close to the front car but still it didn't brake, instead continued at the set speed just as normal cruise control would do. Occasionally it would indicate a detection of a car in front (say 1 out of 3 times roughly) but still wouldn't brake. Annoyingly, it wouldn't give me any error message either. It wouldn't say 'clean the sensor' or 'adaptive cruise control isn't working' or any exclamation mark or anything like that on the dash. It's all indicated as working fine, except it actually isn't. Where do you think the problem could be? Your advice is highly appreciated. Thanks.

 

Thanks for the reply mate. In Australia we don't have 'PCS' button. I think it's on by default. You can't manually turn it off. When I turn on the car, I can see in the dash there is PCS during the initial 2 second check up (where I think computer checks seatbelts, airbags etc) then it goes away (which I believe that system is satisfactory that it's working and switched on).

 

I did bit of research in priuschat itself and found few articles where radar cruise control acting weird but most of those times what happens is, it doesn't get engaged. In my case, everything seems to work, it gets engaged, speed is shown, number of spaces in front of the car where it detects the front car is shown and occasionally the car in front also gets detected but the braking doesn't seem to work. If it gives me any error, i would have been able to trace the item if anything has been failed. This is very dangerous because the driver gets the wrong idea that it works when it actually doesn't.

 

Thanks for the reply. From outside all look clean but I think I should remove the plastic covers and have a careful look inside (radar sensor area and behind the toyota embelm). Will keep you guys posted on how I go. Though I would have expected an error message saying 'clean sensor'. Anyways, will do a complete clean inside out to eliminate the possibility anyways..

 

Hi Johny,
I am positive that I engage radar cruise control because the symbol is slightly different and I can set the distance with the car in front of me etc (which you can't do with regular cruise control). Before engaging it says 'radar ready' and after engaged it would indicate the distance from my car with the set speed on the dash. (Which you won't see with regular cruise control). Am I missing something?

 

Guys, interesting development. While I'm driving the car today I noticed that it detects the front car and brakes accordingly only when I'm sort of driving uphill where my car's nose kind of pointing little upwards. What this concludes is, the radar unit somehow is directed rather downwards hence is missing to detect cars 90% of the time. It seems all I have to do is, remove the bumper and do some adjustments to make it point little upwards. I can't figure out how that happened but it certainly looks like what happened. I will keep you guys updated on how I go.