Passenger airbag off light is on, have to replace seatbelt receptacle $450

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Fishy, Sep 9, 2025 at 7:44 PM.

  1. Fishy

    Fishy New Member

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    Hello,

    Went to dealer, they say the light is on due to faulty seat belt receptacle and quoted $450 for below:

    SRS - Seatbelt: REPLACE PASSENGER SEATBELT RECEPTACLE AND PERFORM ZERO POINT CALIBRATION WITH SENSITIVITY CHECK

    From what I’ve read, the calibration is required, is this something the non dealership I normally go to can deal with or does it need to be the dealership? Assuming I probably can’t do it myself
     
  2. PriusCamper

    PriusCamper Senior Member

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    We call them stealerships because they're going to rob you $450 for a part you can get at your local auto wrecker for $25 and then odds are when it doesn't fix they're going to find the most common cause, which is damage to the wires under the seat that you can easily repair with some wire crimps, but they'll add another $700 to your bill to "replace wiring harness" because they aren't allowed to patch, only replace with new.
     
  3. ChapmanF

    ChapmanF Senior Member

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    The OCS calibration is something you can in principle do if you have a good-enough scan tool and a 30 kg (66.1 lb) solid metal weight to place on the seat (they say to avoid other kinds of weight like water-filled). If you don't have that stuff handy, it's easier for the dealer.

    I'm not positive whether you need the weight for the calibration procedure itself, or only for the sensitivity check after.
     
  4. BiomedO1

    BiomedO1 Senior Member

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    That's normal in my car; unless someone is sitting there. If someone is sitting there the lamp should turn-off and the seat belt chime should activate.
    Not sure how it works on your gen3; but that's how it works on a gen4.......

    Hope this helps....
     
  5. Fishy

    Fishy New Member

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    Sorry I should have specified that it’s when someone is sitting in the seat
     
  6. BiomedO1

    BiomedO1 Senior Member

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    I'd be looking at the seat sensor, rather than the buckle - unless it's some sort of one-piece unit. that sounds like a junk-yard trip to me. Pull it apart and look for busted wires or sensors. Repair and/or replace anything that looks suspicious. Spray contact cleaner on those connectors as your putting it back together.
    I've heard of belt buckle sensors failing to detect the buckle is locked in place, but that's usually due to soda spillage. Firing some contact cleaner down the receptacle will usually fix that.
     
  7. ETC(SS)

    ETC(SS) The OTHER One Percenter.....

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    That's implied.
    If you look under the seat (which is something that the dealer may or may not have done when they were pretending to look at it) and IIRC there an air bladder that enables the AB when somebody's butt is in the seat.
    See of the hose is still connected.

    Not to ask the obvious but is your 2012 equipped with a passenger seatbelt disable switch?
    Some Priuses have them on the co-pilot's side and it's clearly visible when you open the door.

    Good Luck!

    If you have a thirteen year old Toyota you REALLY need to be staying away from the dealer!
     
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  8. ChapmanF

    ChapmanF Senior Member

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    There are four electronic strain gauges, one near each corner of the seat cushion frame, wired to the Occupant Classification ECU.

    Based on the overall weight and how it is spread over the four sensors, the ECU classifies the occupant as AM or AF (adults), Child, or CRS (a child restraint system), and that classification is used to determine if the airbag is enabled or not, and what inflation force to use.

    The strain gauges are affected by just how the seat rails are bolted to the car, so the ECU calibration needs to be redone any time the seat has been taken out and put back in, accessories or seat covers are mounted to the seat, etc.
     
  9. BiomedO1

    BiomedO1 Senior Member

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    So the battery should be disconnected before you start messing with it - hopefully it'll retain the old settings and not need to be re-calibrated?
    So blindly jamming stuff under there is a big NO NO. My spare tire pump lives under there, but it's in a nice fabric case - nothing that's going to hook or pull something down.
     
    #9 BiomedO1, Sep 10, 2025 at 8:30 PM
    Last edited: Sep 10, 2025 at 8:36 PM
  10. ChapmanF

    ChapmanF Senior Member

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    Well, there's a safety reason to disconnect the battery before disturbing any of the bright-yellow, pyrotechnic squib circuits.

    The occupant classification ECU doesn't directly connect to any of those, just the four strain transducers and a buckle switch, and communication lines to the airbag ECU. Whether to disconnect the battery before handling those might be more down to whether you normally do that before doing any kind of electrical work.

    I don't think it forgets its calibration if power is lost. Gen 3 doesn't have a big list of things you're told to recalibrate just because the battery got disconnected. Advanced Parking Guidance is the only thing (in the 2010 repair manual, anyway). In gen 2, the windows would forget where up is, but gen 3 windows normally don't.

    You are, on the other hand, supposed to redo the OCS calibration if (of course) the OCS ECU has been replaced, or if stuff has been added or removed like covers or accessories attached to the seat, or any time the seat has been removed from the car. Setting it back in the car and tightening the rail bolts can put certain strains on the rails and seat that aren't the same every time, so you can't count on the remembered calibration being right if the seat has been out.

    I think the OCS wires are tucked well up into the seat cushion—I don't think anything I've ever jammed under there has snagged them.

    Of course, jamming in anything bulky enough to press up on the seat would probably affect the OCS calibration.
     
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