Brake Pressure Sensors
 

I was wondering if anyone has experience of changing the little in-line brake pressure sensors?

I have the "Anti-skid service required" message on my DIM and I have had my fault codes read showing a faulty brake pedal positioning sensor and faulty brake pressure sensors.

The individual parts are expensive and I am going through a process of elimination as follows:

£120 for brake pedal position sensor - the one that goes into the brake servo. I've got it, installed it but the error message is still there.

There are 2 in-line pressure sensors (pn V30793669) and there are £250 EACH!!!!! I have seen on ebay them available at around £100 for 2 including the holders (pn V3524132) and I am wondering what to do.

I could end up spending £620 here.....

Has anyone any advice on how to fix the faulty sensors. Additionally, is my error message going to go away once I've replaced the faulty part, or will I need to get it reset?

Have you cleared the codes and seen if they have come back? Not been much help here but I had the same codes and I cleared them with vida and they haven't come back.

codes
 

Codes need to be cleared, the test is then, do they come back?
Is your car very new and demand new parts ?.Running an old car ,2001,there is rarely any need for new parts ,except for wearing stuff like pads .I recently replaced the position sensor second hand and it was only a tenner ,I think .You can get quotes for parts from Parts Gateway online .Parts are unfailingly good in my experience and often as good as new
The specialist breakers will have parts out of written off modern types ,so i can rarely see the point of new stuff and its recycling!

I've put the pedal positioning sensor in, but the message "anti-skid service required" is still there.

I was wondering if there's a procedure to test the pressure sensors. Seeing as there are 2, I would prefer to find out which one of them is faulty instead of just going through the process of replacing parts willy-nilly until the messgae goes away!

Scan tool with live data, press the pedal and look at the pressure values

Please could you tell me where I can get access to one of those? I have seen something after Googling it, but guess that type of tool is owned by a garage?

scan tools
 

I think you would need the Volvo specific Vida/Dice set up to get the pressure values .I have only got a multi make reader which will not go into such detail .The Vida is connected to a laptop which must have at least Windows 7 Professional on it .These kits are on ebay from various sources ,but some are hard to make work ,so i read on the forum .If you search the forum there are lots of references to these kits ,but not having one I cannot advise .
Yes ,this is what the dealers use ,but it would be infinitely useful to you too.

You only need a bit of IT knowledge to get it to work, my fiend did mine for me but basically he split the hard drive on my laptop so it's runs 7 professional and Windows 8. Then vida downloaded off a disk onto the Windows 7 side of things. Best money I've ever spent motoring wise. Works on any volvo up to 2014.

I get an intermittent ASSR message. Diagnosed by dealer as pressure sensor no2. But why does it not show permanently. I can go for months without the messge. Then it will appear a couple of times, the disappear again.

Just had the same fault on my V70. I spent £80 on the icarsoft scanner to read the codes.
After clearing them I swapped the sensor wiring plugs from one to the other, if the code changes from sensor 1 to sensor 2 you'll know the sensors is the fault. If not then its possibly a abs ecu fault. I got my sensor from
http://www.volvobreakers.co.uk/volvo...vo-abs-sensor/
You'll need a deep 27 mm deep socket to remove the sensor. Its a bit awkward to get at but straight forward enough to do.
So far so good no warning message.

Thank you! Mine says BCM-0130 Brake pressure sensor 1 - signal too low. Right now I have no idea which is 1 and which is 2, so your method tells me which is which.

As above, mine is temperamental too. The message has appeared randomly in the last 6 months, but within the last couple of weeks it's on more than it's off. It's typical of those types of switches; similar to an Amazon brake light switch which works sometimes when the switch is old!!

The sensors are located on the brake lines behind the fuse box, the sensors are different to the pedal sensors, these are fluid pressure sensors.
They're mega bucks from Volvo so that's why I went for a used one. You can buy a lot of used sensors for the price of a new one :thumbs_up:

used parts
 

I so agree with Chris above .I nearly always use second hand parts .You can if you wish specify that the parts supplied should be Volvo original where it counts ,that way you get the reliability without the out of this world prices .The other week I had to get two of the big bearing carriers that carry the front wheels ,mine were wasted with alu .corrosion and the tester did not like them .Got them from specialist breakers via Parts Gateway and they arrived here in the Highlands ,48 hours later ,good as new and £30 each !I think I would have a coronary if I knew how much they were new !

I think they are £30 new..oops soreee!

Brake Pressure Sensor DIY
 

Hi all Im new to the forum. Owned my 2010 XC90 D5 for nearly two years - superb car...until it goes wrong!

Just had a message on the dash telling me "anti skid service required". Got an Indi to plug into diagnostics and they said that there is internal faults in both 1&2 brake pressure sensors.

A bit of browsing on the internet tells me the parts new are seriously expensive but second hand parts from a breaker are about £15ea!

So question is how easy is it to replace? Looks like a screw off, screw back on job but will I have to bleed the system as well? When I take the current sensors off will that expose the brake lines to air?

On the face of it looks like a simple job but am I underestimating the size of the task here?

Thanks.

Simple! Seriously: dead easy.

Seems a bit odd that both pressure sensors are faulty, but so be it. You're correct; they are about £250 each new. I've not seen them for £15, but I paid £58 for 2 second hand ones incl postage.

They seem to send out second hand parts together with the junctions. In fact, they cut the brake lines to save time. The simplest way is to unscrew the sensors using a deep 27mm socket. A tiniest amount of air could get into the system, so a full bleed afterwards is good advice.

In a seperate thread on the same topic, I incuded a couple photos that might be useful to you:

http://www.volvoforums.org.uk/showth...t=brake+sensor

pressure sensors
 

I did some checking into those pressure sensors, they put out a dc voltage relating to fluid pressure, and the bcm seems to compare the difference, so if your seeing the fault code it might not be complete failure of the sensor needing replacement. You can run a calibrate routine in vida that takes out small differences in the signal level that may fix things for some ppl. I did some long term logging of the outputs from them to get an idea how much they differed during use over time if anyone is interested !

For your parts you should go to Parts Gateway online and get used parts ,which are guaranteed .I got a brake position sensor from a breaker on there ,and, as a surprise to us both there proved to be two posibilities and i got the wrong one .Send it back ?Naw ,I,ll just send you another one foc .Total with postage ,a tenner i think .
Just don;t go down the new parts route .With Gateway ,parts are very cheap and guaranteed .You can't go wrong .
On the codes ,you have to clear them and try again,to see if the fault is fixed .Any goodish generic reader will get you into abs (see diagnstics world )or get set up with Vida ,Volvo specific ,but tells you more than need to know probably .Order some pressure sensors from Gateway and save yourself a bomb .
BUT, you must have a reasonable code reader of some sort for these cars .It is absolutely impossible to run them without and you will soon become an expert ,as ,believe me the will give you lots and lots........and lots of codes to read .I have just sold a phase 2 v70 ,because I just could not be a.......ed with these endless faults .
Now as you see have got a 940 ,which is electronic, but not over the top like the phase 2.

pressure logging
 

Wow Thassos .Not many people will know that!!

Oh that's interesting - I noticed the readouts differed somewhat between the 2 sensors after I replaced the faulty one. My faulty one gave no read out when the brake pedal was depressed.

Brilliant intel on this area people - thanks!

So my code disappeared really suddenly on the very next journey which I thought was odd. The guys who scanned the codes told me it was the sensors and then quoted me around £700 to have it fixed. But since then Ive done nothing and the codes have NOT reappeared.

So Im inclined to put it down to a glitch (maybe a slight voltage drop or something?) and wait to see if the warning message comes back.

The thing nagging at the back of my mind is that the mechanic gave me war and peace about how lots of things will be disabled if the pressure sensors have failed such as 4 wheel drive, abs, bending xenons, cd player etc.....

Cheers!

That's good then! Yes, the message only appears when the sensor or sensors are bad, then the message goes again. Mine started giving random messages about 6 months before giving up the ghost altogether. I have to say though that everything else appeared to be working properly including 4WD and ABS.

However, when the ABS rings were knackered, there were def other faults

Does any one knows how to calibrate the pressure sensors using Vida please.
I've cleaned the ABS pump connectors mo ths ago but abs warning light comes on intermenatly.
Checked it with Sensor 2 low signal and pressure sensors 1 and 2 outside permitted range.

Thank you.

what's the pressure difference between both sensors max is one bar when the pedal is not pressed .When pressed hard they should read the same ish within couple of bar.
to reset them in vida is the next screen after the test sensor screen .

[IMG]https://i.postimg.cc/Bb4CBGsc/20190812-101708.jpg[/IMG]To be honest , I didn't check the difference using Vida. Just found this thread and trying my luck.
Iam not expertise in Vida. I use it clear codes and fi finding fault.
Could you please kindly let me know how to check it using Vida.



Below is the code I took out this morning but cleared it straight away. I think it wil come back again soon, it is an on going issue.

Thank you.

Diagnostics/Vehicle communication/BCM/Advanced tab/open BCM + & -/Calibration then brake pressure sensors.

Hope you find it ok when I did mine 1 & 2 were giving strange reading so had to replace one.

Thank you for that procedure.

Mine showing 10 and 1 bar.

Could that low reading be only sensor fault or do I have leakage some where, which affects the pressure.

How to identify which one is sensor 1 and 2 please.

Thank you.[IMG]https://i.postimg.cc/ZnSvfrmg/20190816-130813.jpg[/IMG]

pesky sensors
 

The 1 bar reading is minus, so makes me think perhaps the sensor is disconnected or completely open circuit perhaps ?, have you tried cleaning the terminals up, also use a dvm to simply measure the voltage across each sensor, should be very similar, also with the brake pedal pressed..

if you want to confirm which sensor is showing the low reading just disconnect one and see which shows a different reading...if your using vida.:o

Thank youThassos.
I will clean the terminals with contact cleaner when I get home.
I have multimeter, I will check the voltage.
Biut Sorry to ask a dumb question .Do I have to check the voltage when the engine running or in key position 2. Also with brake pedals pressed at the same time.

Thank you.

ideas and questions
 

Try some fine wet & dry (its a grey coloured 'sandpaper'), but also use some folded into a spade shape to clean inside the push on connector (dont go too mad and remove the plating from either side).

You can measure the voltage with key in pos 2, to check if you measure any voltage, but to see a full pressure (and full voltage) reading have the engine running and get so someone to press the brake pedal, compare readings on both with (pedal released & pedal pressed) to see what signal the bcm is seeing. no worries no question is stupid, as you always learn something asking questions :teeth_smile:

Don't try to clean the pins with anything as you wil bend them as very thin.
just swap the plugs over if the same reading but different sensor then sensor fault.
They should be close to 0 on both sensors and the same when brake pedal is pressed so approx 120 bar max is 180 i think

If you unplug one sensor it will read -21 bar approx on vida

Ive plugged vida nad found the following results.
Could you please guide me which one is faulty.

Thank you.


Both sensor plugged in without brake pressed
Sensor 1. +10.56
Sensor 2. -.91

Then Both sensor swapped without brake pedal pressed.
Sensor 1 -.91
Sensor 2 +9.49




Then I removed the Left side sensor (when facing the car from front) (closer to engine side).
I call this sensor as Sensor- 1.


The other Sensor which is on right side (when facing the car from front) closer to battery terminal – near side –
I call them as Sensor- 2.

The reading after removing left side Sensor- 1 without brake pedal pressed is
Sensor 1. -.91
Sensor 2. -20.67

And with brake pedal pressed
Sensor 1. 44.98
Sensor 2. 33.93




The reading after Right side sensor- 2 removed (closer to battery terminal)
Without brake pedal pressed
Sensor 1 -20.88
Sensor 2. +9.92

With brakes pressed
Sensor 1. -20.67
Sensor 2. +46.62

it looks like sensor 2 is out a lot in all tests , so change that one first .. It is the difference in pressure between the two sensors which puts the warning message up .

Sorry. Bit confused.
After swapping the sensors wiring , Ive come to conclusion that one of the sensor is faulty.
But to decide which one is faulty is a bit tricky for me.
If some one could please help me with what reading the sensors should produce if one of the sensor is removed and vice versa.
That will be much helpful for me and for future.

Thank you.

You can buy one sensor and try it , then if you still get a problem put it in the other position ... They were £250 each last time i was aware of the price ..

Have you removed the sensor or just unplugged it ?.
If removed one you will now need to bleed the brakes.
Yes Volvo want close to £275 for one but you can get them for £110 Genuine Volvo part .from Skandix part no 1027602 which comes in a Volvo bag with a volvo sticker and part no 30793669 .
But put cars info in on the site parts finder.

Good info on cheaper sensors .
In my long experience doing this job you don't need to bleed the brakes if you are quick as a small amount of fluid runs out down from the reservoir which means the air can't get in ...

Thanks Clan. I've ordered one from breakers.

*Meanwhile I want to be more clear to find out which one is faulty* to reduce the hassle of doing it twice.
I

Removed Left sensor and the reading* are

With out brake pedal pressed
Left side* -20.67****** Right side sensor -0.91
With* brake pedal pressed
Left side* -20.67***** Right side sensor +50.29


Removed Right sensor and the reading* are

With out brake pedal pressed
Left side*** +11.56**** Right side sensor -20.67
With* brake pedal pressed
Left side*** +60.49*** Right side sensor* -20.67

Hope this is much clear reading to understand and.some ine shed some light.

Thank you.

I would have got both from the breakers ...
The readings have always been a bit confusing , You would expect when your foot is off the brake both would read zero but even on a working system with no faults this is not the case. The actual pressures are not that important , what is important is that both pressures are similar when pressed within a certain range ... just change one and see how it goes , if it is still faulty put the one you took off on the other one ...It is all quite easy ..