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Brake Booster Sensor

Discussion in 'Technical' started by bures, Jul 10, 2015.

  1. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    I keep intermittently getting the engine management alarm glowing.
    Maybe like that for a couple of days then goes away
    Time I thought to investigate

    Using my OBDII plug-in diagnostic tool it comes up with:-
    Fault Code PO555 - Brake Booster Pressure sensor

    Has anyone a picture of where this is located under the bonnet
    Searched under the bonnet with no success
    Can anyone tell me where I can find it ?
    --- Double Post Merged, Jul 10, 2015, Original Post Date: Jul 10, 2015 ---
    Forgot to mention, its a Punto Evo 1.4
  2. Anup

    Anup Regolare

    Messages:
    303
    Bangalore
    Bangalore
    Grande Punto 1.3
    Brake booster is located just outside to the Brake pedal, almost stuck to the Firewall right below.
    If you fee the brake pedal is mushy then suggest you do not drive the car, else if the braking is all okay as normal then the ASS guys needs to simply unplug the sensor and blow dry it clean.
    Was you car recently been through a water clog area, if yes then may be dirt/water has gone in else if there is a leak then the hydraulic fluid can clog the sensor.
  3. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    Apologies, do you mean
    (a) inside the car where the clutch/brake/throttle pedals are located
    (b) under the bonnet ( engine compartment) on thebulkhead, all I seem to recall in that area were the pipes on the bulkhead from the air con
    There is no difference in my brake pedal feel whether the alarm is on or off

    I will have a closer look in an hour or so
    Thanks for your speedy reply, very much appreciated
    --- Double Post Merged, Jul 10, 2015, Original Post Date: Jul 10, 2015 ---
    Just looked under the bonnet at the bulkhead area where there is a master cylinder fed from the brake fluid reservoir
    I can see no wiring going to a sensor
  4. Anup

    Anup Regolare

    Messages:
    303
    Bangalore
    Bangalore
    Grande Punto 1.3
    No worries, it's under the bonnet,actually I have the pedal position as the reference point as to where you would need to see under the bonnet.
    Another reference point to you is near the Steering rack(driver side). Getting work done on Brake Booster is sad job, everything inside the bonnet on the Right side will be out.
    The sensor should be accessible from below the car.
  5. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    Anup:-
    and there I was thinking this would be a 5 minute job ?
    I did jack it up today with an hydraulic jack and axle stands but its to dangerous to crawl underneath for me
    I will have to get access to a vehicle hoist so I can safely get under the car.
    Thanks for all your help, you have been a great help to me
    Regards
    alan(UK)
  6. vIjAy_kHaSa

    vIjAy_kHaSa Esperto

    Messages:
    1,353
    Panchkula
    Its not present in Indian cars so I am not 100% sure but that sensor should be in the vacuum hose going to the booster.
    You can try locating sensor with the help of diagrams present in parts catalog of fiat. http://ricambi.l-automobile.com:7080/navi?FORCED=TRUE. Enter your cars chasis no and explore the brake system carefully.
    Last edited: Jul 11, 2015
  7. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    VljAy_kHaSa
    Thanks for the link to the diagrams, brilliant at least I now have a diagram of the relevant parts
    Unfortunately, searching the brake parts section, its makes no reference to this Brake Pressure Sensor
    As you said. possibly not fitted to Punto`s in your location
    Fortunately the dashboard alarm is not always on, which makes me think either the wiring is loose or the sensor just needs a good clean
    On "You Tube" there is a video clip of a Brake Boost Sensor being cleaned with an compressed air line to remove any dirt from inside the mechanism, so it appears from that it may be a common problem
    A used Sensor here in the UK is about £125 Sterling to purchase, so a new one may be double that.
    All that`s inside is a bellows and a couple of electrical contacts.
    see picture brake sensor.jpg
  8. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    Now found part No
    51797783
  9. varunrtr

    varunrtr Esperto

    Messages:
    1,256
    KL-01/ TO
    Grande Punto 1.3
  10. bures

    bures Timido

    Messages:
    9
    Suffolk
    Punto Evo 1.4
    varuntr - Thanks, I have found him on Twitter and sent him a message

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