Problems with Dynamic Radar Cruise Control?

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Hydrocket, Feb 18, 2021.

  1. Hydrocket

    Hydrocket Junior Member

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    Dynamic Radar Cruise Control (DRCC) is "unavailable". I thought it might be due to recent cold snap, but it's been warmer and still not working. Basically, I turn on cruise, it says "Radar Ready" and then when I actually push to set afford control it says "Cruise Control Not Available" with a yellow exclamation mark. No other errors or warnings of any kind.


    So I washed the car and inspected the emblem hoping it was dirty (despite not getting the clean sensor message) No visible damage. No warning on the dash about radar, just that cruise is not available. Pictures included.

    Pre Collision works! Set it as loosely as possible, then approached a couple of cars in the turning lane. Sure enough the "BRAKE" warning flashes on the dash. And I think that system uses the radar? This sure is perplexing.

    It almost feels like a condition in the car is preventing the radar cruise from working. For example, I used to get the EXACT same message in my Lexus LS when I tried to engage DRCC if the traction control switch was in "Snow" setting. Same message, same yellow exclamation mark.

    Is there a switch or setting in the car that could cause this as is did in my Lexus?

    Anyone else experience this? 20210218_071027.jpg 20210218_071041.jpg
     
  2. alanclarkeau

    alanclarkeau Senior Member

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    Is the windscreen clean?
     
  3. Hydrocket

    Hydrocket Junior Member

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    Yes. I washed the car.
     
  4. jerrymildred

    jerrymildred Senior Member

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    There's a list of possibilities in the manual. I put an arrow on one that seems likely if you turned off VSC or traction control and forgot about it.
    Untitled.jpg
     
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  5. Hydrocket

    Hydrocket Junior Member

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    But doesn't that reset after the car is turned off then back on?

    Car has been off/on many times.
     
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  6. jerrymildred

    jerrymildred Senior Member

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    That I don't know. I've never turned it off or looked up the details about it.
     
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  7. Hydrocket

    Hydrocket Junior Member

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    According to the owners manual, it gets reset when the car is shut down...I just checked.

    I DID have it turned off one day, so your post got me to wondering!
     
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  8. AzWxGuy

    AzWxGuy Weather Guy

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    Just adding to the guesses here. Since there isn't a message specifically directing you to "contact the dealer" like in the case of an ECU failure, maybe it's just a regular cruise control issue such as a stuck cancel switch on the brake pedal or dissimilar tire sizes causing an ABS fault. Not even sure if my 2021 manual is representative of 2017 issues. I'll see myself out...
     
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  9. t_newt

    t_newt Active Member

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    Dynamic cruise control doesn't work if you are driving in 'B' mode.
     
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  10. jerrymildred

    jerrymildred Senior Member

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    True, but the pictures show it in Drive.
     
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  11. Hydrocket

    Hydrocket Junior Member

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    Correct.

    But I did have it in Drive.

    Really good ideas thus far, everyone.

    I'm starting to think a trip to the dealer is in order. :(
     
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  12. tdaily

    tdaily New Member

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    So it doesn't work when the VSC is activated or when it has been deactivated? What other options are there?

    Mine was working fine yesterday. And was working for about 10 miles today. Then it turned off while I was driving.
     
  13. jerrymildred

    jerrymildred Senior Member

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    Welcome. The manual is quite clear that it doesn't work if you turn off VSC or Trac control. If it doesn't work with VSC & Trac control on, then I'd be making sure all the sensors are clean. Not sure about your part of Iowa, but where I used to live they have lots of dusty gravel roads. Also, you didn't give any info on how fast you were going or any other factors, so it's pretty hard to give any suggestions.
     
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  14. AzWxGuy

    AzWxGuy Weather Guy

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    Something else you might try before the dealer $$ visit. Try a little careful disassembly down to the radar unit and check the connections. Remove and replace the plug(s) several times. I myself have not investigated this route, and have no idea where the connectors are on the unit. And if there is exposed wiring harness visible from that vantage point, check that also for any signs of "nibbling". Rodents have an affinity for the insulation and other environmentally friendly materials the vehicle is composed of.
     
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