Got my first system malfunction at around 10k miles

Discussion in 'Gen 5 Prius Main Forum' started by Uhcoustic, Jan 11, 2024.

  1. 23PriLE

    23PriLE Member

    Joined:
    Sep 14, 2023
    94
    67
    0
    Location:
    North Central Florida
    Vehicle:
    2023 Prius
    Model:
    LE
    I also had some odd stuff going on with the safety features recently. I didn't get any major "system malfunction" warning but when I started the car I noticed that, in the MID display, it said that PCS and LDA were OFF. This just appeared at startup and then it's gone. It appears so briefly that I almost didn't notice it, so there may have been others too.

    I shut the car off and restarted but no change. When I went into settings to check at least one of them (forget which) said it was ON. So I turned it OFF and then back ON. I forget the exact sequence since I tried a few things. At one point the sensitivity could be adjusted but the ON/OFF option was greyed out.

    Went about my drive, with numerous stops and restarts, but still got the same indication on the MID.

    Later, when I parked close to a barrier, the proximity warning didn't come on and it was shown as OFF too. Also at some point the traction control was also shown as being OFF. I tried turning it back on with the button but that didn't work.

    Oddly, when I finally got home and pulled into my carport the parking proximity warning was working again but the others were not.

    I haven't driven since then but I plan to just keep an eye on it for a while and see if the settings go back to normal. I suppose I should take a pic the next time it goes into ready mode since the notices disappear almost immediately.

    Fortunately, the features that I find most useful (DRCC, LTA, PDA) were still working.

    I've always wondered if the PCS is actually working since I've purposely come up on cars quickly and gotten really close before I chickened out and braked manually. I even reset the sensitivity which then gave me more alerts, and it said it was ON but it's still never done any braking. Perhaps it's been malfunctioning the whole time and I've just never noticed the light on the MID.

    I get braking from the PDA function as I'm approaching a stopped car ahead but when I get closer that turns off and and I brake manually. And when using DRCC the car will come to a stop on its own behind a stopped car if I don't touch the brakes. But I've never gotten any indication that PCS is actually doing anything.

    Has anyone experienced any actual braking from their PCS?
     
  2. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,684
    503
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
    No, but it is a pre-collision system. "When the system determines that the possibility of a collision is high". You'll have to try a bit harder and not chicken out. I suggest something soft though, just in case.

    There's a video here showing it in action, to get a feel of the sort of potential collision it avoids:



    Sounds like you do have something a bit odd going on - I've had things shut off due to blocked sensors or dirty cameras, but not traction control.
     
  3. Uhcoustic

    Uhcoustic Member

    Joined:
    Jul 4, 2023
    53
    28
    0
    Location:
    California
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    Hadn't considered that! not a happy thought
     
  4. 23PriLE

    23PriLE Member

    Joined:
    Sep 14, 2023
    94
    67
    0
    Location:
    North Central Florida
    Vehicle:
    2023 Prius
    Model:
    LE
    The video actually makes me suspect that mine has never been functional.

    I've come up on stopped cars as shown in the video between 2:00 and 2:15, and never got any large orange warning light (beeper might be turned off intentionally). Also, in the video, the car starts decelerating long before the point where I chicken out and brake manually.

    The video indicates a speed of 60 km/h, which is ~36 mph and I'm probably going about the same speed. One difference is that I may take my foot off the accelerator pedal as I'm approaching the car ahead, not just continuing to press it. But I do not apply any brake until I'm quite close and then I brake considerably harder than in a normal stop.
     
  5. Trollbait

    Trollbait It's a D&D thing

    Joined:
    Feb 7, 2006
    22,576
    11,852
    0
    Location:
    eastern Pennsylvania
    Vehicle:
    Other Non-Hybrid
    The system very likely takes into account you letting up on the pedal.
     
  6. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,684
    503
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
    Very likely. It doesn't say so explicitly in the manual that just letting up would be sufficient, but there it's clear that a lot of emphasis is on the PCS not activating if it thinks it may mean interfering with any evasive action the driver is already taking.
     
  7. 23PriLE

    23PriLE Member

    Joined:
    Sep 14, 2023
    94
    67
    0
    Location:
    North Central Florida
    Vehicle:
    2023 Prius
    Model:
    LE
    Perhaps that's true.

    Still, it seems odd that if you're approaching a stationary object like another car at a given speed that it would not give you a warning light / buzzer and/or brake regardless of the position of the throttle. You're still coming up on something rapidly and not braking and if you don't brake there will be a collision.

    It's also odd that I'm not getting any big "system malfunction" warning as shown in the pic the OP posted. I do recall that once or twice there was some big warning that flashed on but it was just a quick flash so I have no idea what it said.

    Funny thing is that before I got the car one of my concerns about these types of PCS systems was that they might be too sensitive. I envisioned a situation where they might actually cause an accident. For example, you're driving at higher speed with a big truck tailgating you and and the car slams on the brakes because maybe an animal runs across the road in front of you. I was relieved to learn that these systems are not that sensitive.

    I do want to make sure mine is functioning as intended, however.

    For now I'll be keeping an eye on the situation and if the issues don't resolve themselves I'll take the car in to be checked at some point.
     
  8. Hammersmith

    Hammersmith Senior Member

    Joined:
    Jul 26, 2021
    1,646
    1,643
    0
    Location:
    North Dakota - USA
    Vehicle:
    2023 Prius
    Model:
    Limited AWD-e
    You've double-checked that Proactive Driving Assist is enabled? I know I turned mine off just after taking possession of my car because I was unsure of its behavior yet and I was driving on unfamiliar roads on my way home. After a couple weeks of getting used to the car, I finally remembered to turn it back on. It's slightly annoying in city driving for me(it starts to brake maybe a half second before I would when coming up to stopped or turning traffic), but it's an overall net positive in terms of safety.

    In the 4 o'clock position of the big round display on the MFD, you should have four symbols in a square. The upper-right is the PDA indicator. It's a bird's eye view of a tiny car with little arcs above and to the left and right. It should be green while driving to indicate it's active. If it's grey or yellow, that's why your car isn't braking like you expect. Grey means it's be deactivated in the settings; yellow means there's a system fault.



    Here's an image of the gauge cluster. The car is in park so all symbols are white. When driving, some or all will change to green. (I'm going from memory, so I think I'm correct.)

    [​IMG]

    The four symbols are

    1 2
    3 4

    1. Dynamic Range Cruise Control
    2. Proactive Driver Assist
    3. Lane Departure Alert
    4. Lane Keeping Assist
     
    #28 Hammersmith, Jan 18, 2024
    Last edited: Jan 18, 2024
    dbstoo likes this.
  9. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,684
    503
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
    Good point. Even if the PCS doesn't kick in, as per the video, surely the PDA Deceleration Assist should. ("The vehicle is gently decelerated so that the vehicle-to-vehicle distance will not be excessively short.")

    That is pretty common when pulling up behind any stopped car and noticeable. When slowing you, a car icon will appear between the lanes above the steering wheel in the middle icon.

    As a general rule, grey indicates inactive; white indicates active/ready (so lanes go white when detected) and green indicates current action (so lanes go green when lane tracing, and wheel goes green when it's currently assisting or controlling steering).

    The PDA indicator itself doesn't normally go green. It only does so during Obstacle Anticipation Assist actions. Those have specific indications on the separate assistance screen, but maybe not on the small wheel/lane display.

    Most common PDA state is to just have the icon be white, and the steering wheel green, indicating it's performing Steering Assist.
     
    #29 KMO, Jan 18, 2024
    Last edited: Jan 18, 2024
  10. Hammersmith

    Hammersmith Senior Member

    Joined:
    Jul 26, 2021
    1,646
    1,643
    0
    Location:
    North Dakota - USA
    Vehicle:
    2023 Prius
    Model:
    Limited AWD-e
    Okay. I was going by memory. Maybe I thought it was always green while driving is because the only time I've paid attention to it was as it was performing an action.
     
  11. 23PriLE

    23PriLE Member

    Joined:
    Sep 14, 2023
    94
    67
    0
    Location:
    North Central Florida
    Vehicle:
    2023 Prius
    Model:
    LE
    The PDA is working fine as it does brake as I'm approaching stopped cars ahead. It slows the car but the braking ceases as you get closer so normal braking is then required. It has always functioned like that in my car so I assume that's normal. DRCC and the LKA (lane tracing) work fine too.

    Running errands today the tiny lights on the left side of the MID, which only light briefly when putting the car in Ready, indicated again that PCS (pre-collision), LDA (lane departure), the stability control and the parking assist were all off.

    The LDA symbol at 4:00 on the display also showed it as OFF.

    When I went into the settings (by selecting the "gear" symbol in the MID) the little graphic displays for PCS and LDA do not say "ON" like the others. But when I held down the button, which allows you to go into the settings and make changes, it said they were "ON". I tried turning them "Off" and then back On but they stayed OFF according to the other lights / displays. I did adjust the PCS warning to come on sooner and that part worked as I got more warnings. So it senses cars ahead but it still says the PCS is OFF.

    The "intuitive parking assist", which detects proximity to objects, was OFF but at times it was ON and worked normally. When I got home and parked it was OFF this time and I got no warning.

    Sensors are all clean. My car has under 2000 miles on it at this point.
     
  12. Uhcoustic

    Uhcoustic Member

    Joined:
    Jul 4, 2023
    53
    28
    0
    Location:
    California
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    I turned PDA off and still (very occasionally) get warning flashes/braking when necessary. I think they just haven't been in a close enough call for it to trigger. Or it's broken.
     
    vvillovv likes this.
  13. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,684
    503
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
    So you had yellow warning lights on?

    Those indicators off of the screen about the safety systems are all warning indicators - warning of faults, or reminding you that something is disabled.

    If they're all off, then everything's working, or at least nothing significant is disabled.

    (Like other warning lights many of them come on before you go into READY mode to show that they're working).

    Okay, interesting, there is a difference in the LDA indicator between US and Europe. Presumably regulatory?

    In Europe, it's yellow if disabled, and no icon if enabled. It never shows white.

    In the US (except Puerto Rico, according to the manual), it's not shown if disabled, and white if enabled.

    Puerto Rico seems the same as Europe, but it uses orange for disabled instead of yellow.

    Could it be that your car is in "Puerto Rico" mode? Can you get the LDA indicator to go yellow or orange by turning LDA off in the settings?

    Where do you think it says that? The top level of the menu gives no indication. The light to the left of the MID is a "PCS off" light. Presumably that's not on. So no light there is indicating the PCS is ON.

    Try actually turning things OFF to see what the display shows when they're off.

    Indicated in the top level of settings? As with PCS, there is an "parking assist off" light to the left of the MID. I can't remember whether that lights up if you manually disable it, but it should light up when it automatically disables it due to covered sensors etc.
     
  14. 23PriLE

    23PriLE Member

    Joined:
    Sep 14, 2023
    94
    67
    0
    Location:
    North Central Florida
    Vehicle:
    2023 Prius
    Model:
    LE
    On my car the little lights that appear on the left side of the MID are all red, not yellow. They display the symbol / icon and say "Off". They don't appear until I put the car in Ready and then they disappear very quickly which is why it can be difficult to identify them all.

    I was going to the gear symbol in the MID's menu to have time to see the list of them and check their status.

    The PCS flashes a small icon to the left of the MID and beeps. This indicates that it senses a car ahead and after I increased the sensitivity setting I get more alerts. But when I go into the gear menu, which displays icons for each of the features in a row, the PCS and the LDA icons do not say ON, like the other icons that are functioning do. When I've gone into that list in the past all the icons were marked on ON.

    Hard to keep track of all the lights that appear and flash on and off in various places much less the difference between cars sold in different markets.

    Obviously, I can't diagnose it myself. As I say, the features I use the most, DRCC and LKA, are functioning fine so I'm not too distressed by the situation. When I take the car in for its 6 month check up I'll have them take a look.

    Though all the new safety features are great (when they work) it seems to me that they are mostly beneficial to owners who would rather play with their phones than drive and pay attention. My cell phone resides in the car console. The last time I turned it on was going to visit family at Christmas so I could listen to Spotify. So I'm obviously not a typical "driver".

    Obviously, my old 2008 Civic didn't have any of these features and I got along fine without them. The only thing that's really important to me is cruise control. I admit that I've gotten spoiled by the advanced features of the DRCC and LKA combo.
     
  15. KMO

    KMO Senior Member

    Joined:
    Apr 15, 2004
    1,684
    503
    0
    Location:
    Finland
    Vehicle:
    2023 Prius Prime
    Model:
    N/A
    Really? Most should be yellow/orange, as seen here.



    They would come on and stay on if things were turned or not working. Specific ones for traction control, parking assist and PCS, and single circular icon indicating other functions.

    AFAIK, the only PCS display is the red pop up on the left-hand side of the screen. Not sure what "a small icon to the left of the MID" would be. Is your car a standard US version, or some sort of import? Your LDA was non US-standard, if you were describing it accurately.

    That's because you can't turn those on and off by short-clicking on the icons - they just lead to the submenu. Not clear why. So they don't indicate ON/OFF status.

    I'm pretty confident you never saw them ever indicate "ON" - you just didn't notice the lack of indication.

    Can't disagree with that. But I think you're over-thinking. If you aren't seeing yellow or red lights, all the major safety functions are functioning and enabled.

    Have you tried turning them off to confirm that you get the yellow lights?
     
  16. CatNinja

    CatNinja Member

    Joined:
    Oct 31, 2022
    51
    28
    0
    Location:
    Hawaii
    Vehicle:
    2010 Prius
    Model:
    III
    @Uhcoustic I had exactly the same issue as you a couple of months back. System Malfunction warning, with the LDA icon in orange. Dealer spent 2 days trying to debug it. Reset the car a few times. Took the entire sensor suite apart. It went away after they put everything back together. Thankfully, it's covered under warrantee. It's been working fine ever since.

    Adding this post as another data point in case this is a common issue. Make sure you bring it in so it's a documented issue and covered in case it happens again.
     
    Thunderstrom and Uhcoustic like this.
  17. Uhcoustic

    Uhcoustic Member

    Joined:
    Jul 4, 2023
    53
    28
    0
    Location:
    California
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    Good to hear it was resolved! I took it in for scheduled service today. Four hours later, they told me to reschedule for further diagnostics - they were unable to fix it at that time. Also, the heated steering wheel stopped working. So that's great.
     
    vvillovv and bisco like this.
  18. Thunderstrom

    Thunderstrom New Member

    Joined:
    Jan 27, 2024
    1
    0
    0
    Location:
    Virginia
    Vehicle:
    2022 Prius Prime
    Model:
    XSE Premium
    Im having the same problem, waiting for my dealer appointment, hope they fix this issue. Not happy how sensitive toyota is becoming. I love this car but looks it will be fragile as compare to previous models.
     
  19. Uhcoustic

    Uhcoustic Member

    Joined:
    Jul 4, 2023
    53
    28
    0
    Location:
    California
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    Just got my car back from service - exactly as CatNinja said, it took them two days, deconstruction of the dash/sensor suite, and they fixed it under warranty. The heated steering wheel also stopped working, but that was just a loose connector and an easy fix.
     
    vvillovv likes this.
  20. GeoJ

    GeoJ Active Member

    Joined:
    Jul 2, 2023
    163
    164
    0
    Location:
    United States
    Vehicle:
    2023 Prius Prime
    Model:
    XSE
    I have this issue with the System Malfunction, intermittently. At first it would go off pretty quick, now seems to be more frequent. Perhaps ice on the sensors triggered this last one.

    I had it at the dealer for something else, they checked it but not the full deconstruction of the sensors described in the last few posts. Dealer said if it goes off, don't worry about it. I'm not crazy about deconstruction, and two days in shop, but it may come to that if the warning stays on.