PRE-COLLISION SYSTEM UNAVAILABLE

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by PriusRos, Aug 28, 2017.

  1. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    Last week on a trip home from the airport, I noticed the big message on the display PRE-COLLLISION SYTEM UNAVAILABLE, and a blinking icon of a car crashing. This is the first time I had seen these messages. I had been gone for 12 days - hubby drove me to the airport in my 2016 Prius and dropped me off, drove home and parked it head-first in the driveway, then didn't use it again until he came to fetch me from the airport.

    After checking the manual to see if somehow I had inadvertently turned it off and not finding anything, I took it to the Toyota dealer. At first, they told me it was just some dirt/debris around the sensor (the logo in the front) that needed cleaning. But when I went to pick up the car, the messages were still there! So I had to leave the car again while they figured out what the problem was. To cut a long story short, they said that the front sensor, located behind the Toyota emblem, was putting out all sorts of error codes as a result of being damaged/dislodged by some sort of impact. They compared it to another Prius with a working PCS, and mine was loose compared to that one. They recommended first recalibrating it to see if that fixes it, if not, the sensor itself would have to be replaced. And since they determined that it was due to being damaged, it wouldn't be covered under the new car warranty. Just the recalibration would cost $340.

    I did not hit anything and, as far as I know, nobody hit me. The warning message wasn't there when I went to the airport, and nothing happened to the car in the two weeks that I was away because, other than hubby driving it home and then back to the airport to pick me up, it was parked in the driveway face-forward the whole time. There are some very tiny abrasions/scuffs around the Toyota emblem, but they look old and there is nothing that suggests a hard impact. The licence plate, a new one I had installed a few months ago and which sticks out further than the emblem, is in pristine condition. The last time I had the car in the shop, other than for routine service, was for hail damage repair about 15 months ago.

    I declined the recalibration until I find out if there is any other possible explanation. Any ideas?
     
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  2. CooCooCaChoo

    CooCooCaChoo Active Member

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    I would push for warranty work on it. It would be obvious is there was damage from a front end collision. Dealers will always try to screw you on something, so screw them first.
     
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  3. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    I agree that if I had had a front-end collision, there would have been obvious damage. And it doesn't make sense that the PCS could be dislodged by a small impact that doesn't even leave a dent. The type of "damage" I have looks like a couple of small dings that might have been made by road debris. The problem is that unless I find other people who have the same problem with the PCS, it seems to be my word against theirs. So I don't know how I can get them to fix it under warranty if they say it's not covered.
     
  4. RCO

    RCO Senior Member

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    Could you try escalating your problem to Toyota USA. I don't know if @Prius Team is still watching the forum.
     
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  5. Beachbummm

    Beachbummm Senior Member

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    the more toys the more problems.. hope its covered
     
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  6. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    I called Toyota Care and basically they said that they rely on the dealer's shop to determine whether the problem is covered under warranty or due to external factors (such as a collision). She said they do not have any records of similar complaints. My only recourse, apparently, is to get another dealer to take a look and see whether they come to the same conclusion.
     
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  7. Tideland Prius

    Tideland Prius Moderator of the North
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    Yes I'd definitely get a 2nd or 3rd opinion.
     
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  8. alanclarkeau

    alanclarkeau Senior Member

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    It sounds like it's that sensor, seeing it is loose. But I don't think it is the only sensor - I thought I read that the windscreen also housed a camera type sensor - the grille emblem is RADAR.

    upload_2017-8-30_22-39-45.png

    Is the windscreen clean?
     
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  9. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    Yes, they told me the sensor behind the emblem works in conjunction with two other sensors behind the the rear-view mirror mount, so I would imagine they checked those as well. And they did run the car through the car wash.
     
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  10. Elektroingenieur

    Elektroingenieur Senior Member

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    Do you know which Diagnostic Trouble Codes (DTCs) were present?

    For example, the troubleshooting procedure in Toyota’s Repair Manual (available by subscription to techinfo.toyota.com) for DTC C1A10 (Front Radar Sensor) begins with replacing the radar sensor assembly. The procedures for DTCs C1A11 (Front Radar Sensor Incorrect Axial Gap) and C1A14 (Front Radar Sensor Beam Axis Not Adjusted), in contrast, begin with adjustments.

    If the radar sensor assembly is loose, but there is no evidence of collision damage to other nearby parts, it’s plausible that the sensor assembly was improperly mounted or inadequately secured at the factory, or that its design or manufacture was inadequate to withstand the ordinary demands of use in a road vehicle. I think of these as defects in material or workmanship, and I would expect them to be covered under the warranty.
    In case you’re curious, the recalibration, called the “millimeter wave radar sensor assembly adjustment” in the Repair Manual, requires a level surface with a 5 m × 6 m open area in front of the vehicle, a Toyota Techstream diagnostic system, and some special service tools: Reflector C (09870-60040) and the Stand Base (09870-60010). All of these are essential items that every Toyota dealer should have.

    The adjustment has its own error codes, different from DTCs and numbered 1 through 15. Most of these codes indicate mistakes in following the adjustment procedure, such as a reflector placed in the wrong position, not faults in the car or its parts.
    Trying another dealer might work, though if two dealers agree that the problem was caused by unrelated damage, it could be harder for you to rebut this later. You might also be able to use the Dispute Settlement Program, described under “Step 3” in the “If You Need Assistance” section of the Warranty and Maintenance Guide (PDF) that came with your car. There may be other possible remedies, best discussed with a lawyer.
     
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  11. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    I'm attaching the diagnostics below.

    PCS_DTCs.jpg


    Thanks for the tip about dispute settlement. I will give it a try but I doubt I'll get anywhere.

    I did go to another dealer and they basically said the same thing, that it was hit, although they were a little more specific about the damage they were talking about. The picture below shows the front emblem. It's hard to see but about two-thirds of the way down, below the center of the emblem, there is a very shallow dent on each side of the surrounding area (white part, not the emblem). Also, there is a hairline crack just below the vertical oval in the emblem itself. It looks like it was hit head-on by a horizontal bar, causing dents on both sides of the emblem but nowhere else. You can see that there is no evidence of any damage to the surrounding area (except for the little ding on the left) or license plate and holder, which stick out further. I had installed the new license plate in June.

    What's so confounding is that I am positive that nothing hit the car between the time that the message was not there and the time it came on. Apart from the trips to the airport and back, it was parked in my driveway facing forward. Even if someone had hit it, say while rolling out the trash can or something, I can't imagine it being hit head on right in the center and not cause any damage or scuffing on the side. I also can't imagine a tree branch hitting it horizontally. If this had been a result of something that occurred earlier, the message would have come on then.

    PCS_FrontEmblem.jpg
     
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  12. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    I just went out and looked at the emblem again. I actually can't see the crack in the emblem that they said was there. In the above post, I said that there was a hairline crack underneath the vertical oval - but in fact there's a matching line above the oval as well, so I don't think it's a crack and don't know what they were referring to.

    And again, while I don't know how or when it got hit, I don't see how an impact that causes such minor damage to the body would damage the sensor. You can hardly see the dents and have to feel them to tell that they're there.
     
  13. WilDavis

    WilDavis Senior Member

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    Take it back to the dealer, and in the meantime, I would strongly suggest that you avoid doing any pre-colliding until you've sorted out the problem! ;)
     
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  14. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    I'll try! (y)
     
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  15. CooCooCaChoo

    CooCooCaChoo Active Member

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    Have you asked your husband if the Prius was in any kind of accident regardless of how small or minor?

    Even if he just kissed a wall or another car might actually do it.
     
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  16. bestmapman

    bestmapman 04, 07 ,08, 09, 10 and 16 Pri

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    I have had it happen twice on my 2016. Mine resets automatically after a few days. You could let it go for a few days and see what happens.
     
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  17. Elektroingenieur

    Elektroingenieur Senior Member

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    This is reasonable advice. It’s a PriusChat cliché, but if the car was not operated for 12 days, it’s not entirely out of the question that the trouble was caused by low auxiliary (12-volt) battery voltage when the car was first started after being parked. The Techstream Health Check report @PriusRos kindly shared includes DTCs—all in history, none active at the time of the report—from several different systems:

    LKA/LDA
    C1A47 – Steering Angle Sensor
    C1A50 – Brake System Malfunction
    U0235 – Lost Communication with Cruise Control Front Distance Range Sensor

    Front Recognition Camera
    U0235 – Lost Communication with Cruise Control Front Distance Range Sensor

    Combination Meter
    B150A – Lost Communication with HMI-LAN
    U0163 – Lost Communication with Navigation Control Module

    Main Body
    B1244 – Light Sensor Circuit Malfunction
    B124B – Automatic High Beam System
    B1273 – Sliding Roof ECU Communication Stop
    B2430 – LED Headlight LH Circuit Malfunction
    B2431 – LED Headlight RH Circuit Malfunction

    Smart Key
    U0142 – Lost Communication with Main Body ECU
    U0155 – Lost Communication with Combination Meter

    Navigation System
    B1579 – Voice Recognition Microphone Disconnected
    B15FE – XM Tuner Antenna Disconnected

    Pre-Collision 2
    U0235 – Lost Communication with Cruise Control Front Distance Range Sensor

    Power Source Control
    U0140 – Lost Communication with Body Control Module​

    Of all these codes, only one, U0235, relates directly to the millimeter wave radar sensor assembly. The Repair Manual says it’s recorded “When the power switch is on (IG), a communication error between the millimeter wave radar sensor assembly and the driving support ECU assembly is detected for approximately 1 second.”

    Interestingly, neither DTC C1A10, indicating that the radar sensor assembly detected an internal malfunction, nor any other DTC from the radar sensor assembly itself, were recorded.
     
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  18. CooCooCaChoo

    CooCooCaChoo Active Member

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    ^^^ That sounds more likely as well. The aux battery is known to be the cause of many problems if it is dying or low on charge on previous generations.
     
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  19. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    Yes, I've asked. He says nothing happened to it driving back from the airport after dropping me off and driving to it after picking me up. I know he didn't drive it while I was away because I checked the ECO Diary.
     
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  20. PriusRos

    PriusRos A Fairly Senior Member - 2016 Prius Owner

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    It's been nearly two weeks now and it's been on the whole time. I can turn off the message just by turning off the pre-collision system but the message returns when I turn it back on.
     
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