Prius Adaptive Cruise Control Acting Weird

Discussion in 'Gen 3 Prius Main Forum' started by ppnuwan, Jan 21, 2019.

  1. ppnuwan

    ppnuwan Junior Member

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    2012 Prius c
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    Three
    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.
     
  2. Pluggo

    Pluggo Active Member

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    Just on a whim, make sure the pre-crash braking off switch is in the normal position. It's located at the bottom edge of the dash, under the steering wheel and a bit toward the right side. When it's off you won't get pre-collision automatic braking, and I'm just guessing here, but maybe it will also prevent your cruise control from responding to the car in front of you. Other than that, make sure your radar transmitter is in place behind the Toyota sombrero, and that the connections to it look OK. Send updates...
     
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  3. ppnuwan

    ppnuwan Junior Member

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    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).
     
  4. ppnuwan

    ppnuwan Junior Member

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    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.
     
  5. I'mJp

    I'mJp Senior Member

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    The times that my cruise became wonky, was when there was ice / snow on the front badge.
    Maybe I shouldn't have been using cruise during snow, but that a different topic.

    Could you have a heavy coat of dust ? Dust could accumulate behind the badge as well.
    A blast with an air compressor could clear it out if it is.

    jp
     
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  6. ppnuwan

    ppnuwan Junior Member

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    Three
    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..
     
  7. Johnny Cakes

    Johnny Cakes Active Member

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    So you are saying this is working like "regular" cruise control rather than "dynamic radar" cruise control?

    I'm sure its stating the obvious, but the car has both. You ARE engaging the dynamic cruise control and not the regular cruise control, right? Each is engaged differently, but the car has both.
     
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  8. ppnuwan

    ppnuwan Junior Member

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    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?
     
  9. ppnuwan

    ppnuwan Junior Member

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    Three
    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.
     
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