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ICS Malfunction during wet weather (again)

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by Plugin_RK, Oct 7, 2024.

  1. Plugin_RK

    Plugin_RK Member

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    We've had the dreaded "ICS unavailable" and "Clean Parking Sensors" messages a few times in our 2018 Prius PHV (aka Prime, plug-in). Each time it's been during wet weather - only wet weather, never after a car wash. The only solution seems to be dry weather when it takes just a few hours of dry, warm, sunny weather to clear up. No amount of cleaning sensors helps.

    The ICS problem has been discussed on PriusChat several times e.g.
    Cleaning Radar SENSORS | PriusChat
    New to Forum. Proximity Sensor Issue | PriusChat
    [Poll] "Clean Parking Assist Sensor" and Intelligent Clearance Sonar Issue?? | PriusChat

    There are generic explanations and solutions also on the internet e.g.
    Toyota ICS Malfunction (Solved & Explained)

    Generally, it appears that replacing sensors is the only real solution. However, there seems to be little/no discussion about Flaming's observation:
    On two occasions we also had "ICS unavailable" messages after using the front defroster on wet days.

    Questions
    1. Is there some way to determine which of the many ICS sensors is causing the problem?
    2. Is it possible that condensation inside the camera housing high on the inside of the front windscreen could also cause the ICS error sometimes?
     
    #1 Plugin_RK, Oct 7, 2024
    Last edited by a moderator: Oct 8, 2024
  2. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Just editorial: you mean to say “ICS”, Toyota’s acronym for “Intelligent Clearance Sonar”?
     
  3. vvillovv

    vvillovv Senior Member

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    2: sure, it's possible
    Other things that might cause the message (since you mention "only solution seems to be replacing sensor(s)" ) seems to me an indication of a sensor connection issue of one kind or another.
    Which sensor(s) contribute is probably known by a few mechanics that have been successful with the repair since digging through the repair manual after isolating (if repoducable) with the diagnostic software as much as that will reveal or not reveal about which connection to which sensor in any one particular Prius.
    It could be a common issue or it could be a similar issue depending on which model and / or year.

    My Prime does't like wet weather either, but so far I don't get many messages about systems going offline that don't clear in a timely way.

    Another thought and an easy way to see if you can fix the problem using the HAVC system (since I don't know how you typically set it on wet days when the issue shows up) turn off the HAVC auto mode, raise the heat setting, keep the A/C ON and most importantly switch the Drive modes to Power Mode and HV Mode to keep both the engine and the HAVC system running (not cycling like they do more of in ECO Modes) and drying out the whatever might be damp or wet in the cabin.
     
    #3 vvillovv, Oct 8, 2024
    Last edited: Oct 8, 2024
  4. Plugin_RK

    Plugin_RK Member

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    Yes. You are are correct, thank you. I've asked for this typographical to be corrected.
     
    #4 Plugin_RK, Oct 8, 2024
    Last edited: Oct 8, 2024
    Mendel Leisk likes this.
  5. Plugin_RK

    Plugin_RK Member

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    I have twice tried heating the car strongly with A/C on and motor running while at highway speeds and with MODE on NORMAL, whcih keeps the motor running. The cabin got hot (so opened a window a bit) but the ICS malfunction remained until the weather changed a day or two later.
     
  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Yeah "ICE is not available" sounded pretty dire, lol.
     
  7. vvillovv

    vvillovv Senior Member

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    Kinda indicates to me you've got an exposed connector. Always lots of fun finding those, a lot like rattles.
     
  8. Plugin_RK

    Plugin_RK Member

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    Yes, that does sound logical. Would, it be possible via the OBD port with appropriate software to localise the fault, do you think?
     
  9. vvillovv

    vvillovv Senior Member

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    I doubt even techstream would help with an intermittent issue like that. There are probably no codes, but if there are a bluetooth adapter and an app might be able to pull the code(s) which might make it somewhat easier to find the problem.
    I found many times that simply unplugging the devices and plugging them back in sometimes magically fixes non diagnose-able transient issues. It sounds like the repair manual is also needed to find which and where the sensors in the ICS system are .

    I think that would be fairly close description of what a mechanic would do if you took the car in while it was exhibiting the error message.