Technical Brake Booster Sensor

[ted]

I keep intermittently getting the engine management alarm glowing. At the same time my "Start - Stop" stays permanently in the ON position
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 the net for its location, but drawn a blank
Where is it ??

Thanks

 

[ted]

Getting desperate
Doesn`t anyone know where this sensor is located

 

[ted]

No found part number
Fiat 51797783

 

[varesecrazy]

No found part number
Fiat 51797783

so where is it located/ fitted..??,

Charlie

 

[ted]

I wish I knew, I have searched under the bonnet with no success
I am not convinced if I bought a Haynes Manual that would tell me.


See this page
http://ricambi.l-automobile.com:708...REVIOUS_KEY=ADV_SEARCH&SB_CODE=-1&WINDOW_ID=1

That`s taken from a Fiat site in "India",

Part numbers 10 and 11, but they not on my Evo,
For some reason I cant upload the left image to this forum

 

[ted]

Purchased Haynes Punto/Evo workshop manual.

"Brake pressure sensor" marked on Electrical circuit diagram
BUT no mention of it in the text anywhere
So that was a waste of my money then !!!!!!!!!!!!!!!!!!!!!!!!!

 

[ted]

Salmons Colchester

With no options open to me finding this sensor, I decided to pay Salmons the main Fiat dealer in Colchester a visit
First visited PARTS who very abruptly told me to visit SERVICE.
On SERVICE desk young lady aged around 20
Explained that I wanted to buy a new sensor, I would fit it myself if they told me its location
Loads of flannel about OBD codes not being reliable and the car required further investigation into this Management Alarm.
I asked her to speak to a technician about this problem, the lady then disappeared into the workshop
5 mins later returned with more flannel, did the OBD code explain precisely what was wrong with the sensor.
Yes, its failed !!!!
Now getting agitated and asked if I could speak to the Technician myself, I was told this was not possible.
I said " can you give me straight answer to this request " If I buy the sensor from Parts can someone tell me where its located"
Salmons :-No
OK, If I let you fit the sensor can do that ?
Salmons :Yes
Me: so you must know its location
Salmons : Yes, but I am not at liberty to tell you where

Me:- are you saying that any parts purchased from Salmons must be fitted by Salmons
Salmons : Don`t be absurd
Me:- but you have just told me that I must have my sensor purchased from Parts fitted by your garage
Salmons : That`s true
Me:- Your last two replies contradict each other

At that point I lost the will to live and departed to reach my Blood Pressure tablets.
Never set foot through their doors again

 

[cmosfxx]

Re: Salmons Colchester

I can't see it as a part on ePER so I'm not sure this car has a brake boost sensor.

But if it does, look near/on brake servo. This is where these sensors located normally.

Sometimes electrical/battery problems can cause error codes too.

 

[ted]

Re: Salmons Colchester

I can't see it as a part on ePER so I'm not sure this car has a brake boost sensor.

But if it does, look near/on brake servo. This is where these sensors located normally.

Sometimes electrical/battery problems can cause error codes too.

This has crossed my mind as well. If I cant find it, is it really fitted
On the right side of the engine on the battery side
Between the battery and the bulkhead is an aluminium block with umpteen brake type pipes fitted
What is that ? Cant fin a sensor or vacuum pipe fitted to that
Is that the ABS thingmajig ?

I have also looked at the master cylinder area the bulkhead side of the steering wheel but nothing there
Can you just confirm where I find the brake servo ??

Thanks for your interest, any suggestions are more than welcome

 

[cmosfxx]

Re: Salmons Colchester

Yes this is the abs.

Follow the lines from the brake reservoir and you will find the servo It's the big black round thing.

See if there is a sensor there (near/on the vacuum hose)

 

[ted]

Re: Salmons Colchester

Yes this is the abs.

Follow the lines from the brake reservoir and you will find the servo It's the big black round thing.

See if there is a sensor there (near/on the vacuum hose)

I think I have made some progress

See my pics:= evo 3 and 4.jpg
It looks to me that thought the servo is the other side of the bulkhead in the drivers foot well
I can see one vacuum pipe going into that servo ( not shown on my photo)

Tracing that airline along the rear of the engine I come to:-
evo 1 and 2.jpg
This airline goes into this "thingamjig" and then comes out to the engine manifold
I say manifold, difficult to say as it buried under the aircleaner, but it certainly goes into the block
If you enlarge bottom right pic (evo1.jpg) you can read my text

So it seems as though that may be the brake pressure sensor - I did look at it days ago but I dismissed it as it didnt look like the part number I found on the net

I would appreciate you comments on what I have found

 

[cmosfxx]

Yes this must be the sensor.

Looks like it's a complete part with the vacuum like.

 

[ted]

Yes this must be the sensor.

Looks like it's a complete part with the vacuum like.

Brilliant
I was mislead looking for a part as per my attached photo

Still with your valuable help I am satisfied this is the part in question
What I could do is slip off the wiring connector and see if that brings up the relevant code error

Also a bit miffed after spending ££`s on a Haynes Evo Manual, to find it makes no mention of the sensor in the text, although its shown in the wiring diagram
The latest manuals are paper back with recycle paper but worse than than that, half the depth (number of pages) than the vintage hardback versions
Useless book and certainly not worth the full price of over £20 Haynes want for it direct.


Once again thanks, your time very much appreciated

 

[cmosfxx]

No problem don't mention it.
Have a look at the attached screenshot from ePER.

part #2 .
(put your VIN to find the correct serial )


Of course try to unplug-plug again the cable maybe it's just a poor connection.

 

[Andy Monty]

Re: Salmons Colchester

With no options open to me finding this sensor, I decided to pay Salmons the main Fiat dealer in Colchester a visit
First visited PARTS who very abruptly told me to visit SERVICE.
On SERVICE desk young lady aged around 20
Explained that I wanted to buy a new sensor, I would fit it myself if they told me its location
Loads of flannel about OBD codes not being reliable and the car required further investigation into this Management Alarm.
I asked her to speak to a technician about this problem, the lady then disappeared into the workshop
5 mins later returned with more flannel, did the OBD code explain precisely what was wrong with the sensor.
Yes, its failed !!!!
Now getting agitated and asked if I could speak to the Technician myself, I was told this was not possible.
I said " can you give me straight answer to this request " If I buy the sensor from Parts can someone tell me where its located"
Salmons :-No
OK, If I let you fit the sensor can do that ?
Salmons :Yes
Me: so you must know its location
Salmons : Yes, but I am not at liberty to tell you where

Me:- are you saying that any parts purchased from Salmons must be fitted by Salmons
Salmons : Don`t be absurd
Me:- but you have just told me that I must have my sensor purchased from Parts fitted by your garage
Salmons : That`s true
Me:- Your last two replies contradict each other

At that point I lost the will to live and departed to reach my Blood Pressure tablets.
Never set foot through their doors again

you didn't do the jaffa cake method..

ignore all the fancy desks wander round to the workshops wave jaffa cakes at a older looking guy in overalls covered in grease.... and say excuse me you dont happen to know where part XXX is hidden on my punto evo do you?.. hand over jaffa cakes and no doubt he will let you in on the secret

 

[ted]

No problem don't mention it.
Have a look at the attached screenshot from ePER.

part #2 .
(put your VIN to find the correct serial )


Of course try to unplug-plug again the cable maybe it's just a poor connection.

CMOSFXX - SPOT ON THEN and Top technician ( I use the that word as we don`t seem to have "mechanics anymore" in main dealers
Yes I am hoping that`s all it is, as the blooming light comes on, then after hours, days or even minutes it will go out
I will clean up the connector asap. I have seen on "You Tube" where they clean up the sensor with an air line - not sure if that would rupture the bellows inside !

ANDY:- taking Jaffa cakes never crossed my mind, should have taken some "rock cakes" instead, to hurl at the moron on the Service desk
I knew when I walked in her direction, it was a lost cause
She was obviously primed to get as many customer repairs through their doors as possible

I am in my senior years and this is the first time I have ever come across a garage that blatantly refuses to help you
I can appreciate they may not want to give out information but what about Customer Service, as owning a Fiat I may well be in line to change my car at a later date.

All the time I kept getting "waffle" about how it could be many other things and only a Fiat main dealer could diagnose the problem with certainty
Over the years I have many other makes ( This is my first Fiat) and all other garages have looked on their screens and given me loads of assistance
Good job I bought the car from Desire at Diss, as I wont be putting my foot over Salmons doorstep when it comes to changing my car !!

 

[Frank v]

can eney body tell me where I can buy a 2pin brake boost vacum sensor for my 500 1.4 sport .