Prius c Headlight leveling sensor/module

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Ferni_b, Jun 19, 2024.

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  1. Ferni_b

    Ferni_b New Member

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    Vehicle:
    2015 Prius c
    Model:
    One
    Can someone please help me keep my sanity.

    I just bought my 2015 Prius c and it has a message on the dash display that reads “check headlight system”. I have tried to do my due diligence and land find the solution myself, but I can’t find anything for a Prius c. Everything I have found has been for the normal Prius. I even found some info for the Prius v, but nothing for the Prius c/aqua. The solutions I have found were to unplug the “headlight leveling module” that is located behind the glove box. I removed my glove box it’s not there. I have also found info to check the bracket that holds the sensor that is mounted on the rear suspension. I checked that too. It’s not there.
    So either I am blind and dumb, or this car has those items in completely different locations. Can someone please tell me where these things are located on the Prius c. I’m sure it has to have them, but I’m assuming they are in a different locations.
    Thank you in advance to anyone that can lend some help.
     
    #1 Ferni_b, Jun 19, 2024
  2. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

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    Vehicle:
    2018 Prius c
    Model:
    Two
    I don't think the Prius c ever had a leveling system because it was never offered with HID-type headlights.

    The oldest ones had simple halogen headlights, and the newest ones have all-LED headlights.

    But from mid-2015-2017? (as far as I can tell) they used LED low beams with halogen high beams. Again, no leveler required, but there can be other types of problems.

    Have you verified that all four lamps are working? Any chance somebody installed the wrong bulb type in the high beam sockets before you got the car? The low beams aren't likely to be socketed bulbs but the high beams are.

    Our Prius c gave a whole slew of errors including a headlight malfunction when the real trouble was with a rear wheel bearing. Data from the embedded speed sensor was apparently used somehow for the automatic high-beam control.

    I don't know if a 2015 would have that auto high beam system, but honestly at that point the right move would be to scan the car with a good Prius-aware diagnostic scanner. Very handy thing to have if you want to DIY your maintenance and skip dealer costs.

    I bought an Autel AP2500E to help me with that speed sensor issue and it saved me its cost right away. The similar model AP200 is also well regarded. Both under $75.

    You should also know that you can download the original owners manuals free from Toyota, and you can access the factory repair manual via subscription when needed. It's well worth the cost.

    Good luck!
     
    #2 Leadfoot J. McCoalroller, Jun 20, 2024
  3. Ferni_b

    Ferni_b New Member

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    Vehicle:
    2015 Prius c
    Model:
    One
    Thank you for your help.

    After you message about the wheel speed sensor I went out to my car and did a little more troubleshooting with the wheel speed sensor in mind. All the lights function as expected. I don’t think I have automatic high beams. I work at night and I have never seen the high beams automatically come on, but my Prius c is a one model so I think other trim levels might have that feature but I really don’t think mine does.

    But, I did go out to my car and turn the low beam and high beam lights on while parked with no warning. The next thing I tried was turning on the low beams while parked then bounced the car. As soon as I bounced the car while parked the warning appeared. I wonder what else is connected to the headlight system that would cause the warning when bounced. I almost feel like there is some kind of accelerometer in this thing some how that recognizes the cars tilt but I really don’t know.

    I am definitely going to but that code reader you suggested. I figure it’s a small investment that can save a a lot of dealer repair costs.

    as far as the lights I am going to verify that they have not been replaced. If they have been replaced is there something specific I should be looking out for?
     
    #3 Ferni_b, Jun 20, 2024
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
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    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    A bad electrical connection can be pretty sensitive to bounces. Doesn't even have to be anything high-tech.

    Glad you feel that way- I think a lot of people would enjoy their Prius c more with the peace of mind of getting their own comprehensive diagnostic reports. And based on my recent experience plus the words of many others, these Autels really deliver the goods.

    This is what should be installed in your high beam sockets:

    [​IMG]

    (generic 9005 lamp)
    ​
    This is an example of something you might find, that could cause the car to throw errors:

    Screenshot 2024-06-21 at 12.10.47 AM.png
    (9005 LED stack module)​


    And honestly it could be as simple as a crummy connection between the wiring harness and one of these, or the low-beam LEDs.

    The nose of your car is a little different from ours, so I'm not sure how best to access these bulbs and wiring points. It might be obvious with the hood up, but there may be more to it.

    Note- Don't touch the glass on a real halogen bulb like in the top picture. They're very sensitive to dirt and even skin oil is a problem. Clean with alcohol wipes if needed.
     

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    #4 Leadfoot J. McCoalroller, Jun 21, 2024
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