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Mike, Technician
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Experience:  Tech Expert
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I have a 2010 SAAB 9-5 Auto Diesel Estate where brake warning

Resolved Question:

I have a 2010 SAAB 9-5 Auto Diesel Estate where brake warning chime & light (briefly) comes on after braking i.e. after brake pedal has been released. Brakes have been checked & nothing has been picked up on diagnostic check. What might be the cause of this?
Submitted: 3 years ago.
Category: Car
Expert:  Mike replied 3 years ago.
Hello and Welcome..

My name is XXXXX XXXXX Im happy to help you...

Did you have the diag tests done when the fault light was on / coming on?

Do you happen to know what sort of test equipment was used / what type of garage did the tests?

When it occurs - how does the pedal feel?

What mileage does the car have ?

Rgds, MIKE..........................................
Customer: replied 3 years ago.
Hi Mike, here are the answers to your questions:
Fault was not there when check done.
Do not know type of machine, but it is a Saab specialist & told that equipment should have indicated previous fault. (I have not been charged by garage.)
Pedal feels quite normal but I should say that "alarm" came on yesterday, before I released the pedal.
Car has done 42,000.

Leave it with you.


Expert:  Mike replied 3 years ago.
Hello there Bob -

Thank you for your reply and further info -

Given what you have described, this is usually a fault wither in the vacuum system - ie, servo, servos circuit valve, or vacuum pump - or, a fault with the Abs pump .

The problem at the moment silly as it sounds, its not bad enough , for the Ecu to detected the fault and out the fault lights on - meaning there would be then fault codes logged - which on test - would highlight which of the faults above is the cause.

When I asked about when it was tested, this is as I thought - with no faults showing on the dash - or the fault not there / happening - then it wont register on the machine... so that is not really a waste of time - in that it backs up what Ive said above.

SO - essentially, the fault is going to have to manifest itself more so - so that the computer ( ecu ) detects it properly and switches the fault light on permanently - and hence, that then is the time to have the diagnostics done... because as again as above, there will be fault codes then to determine the fault cause properly - and then it can be fixed.

The only other way is to physically replace parts in the system - substitution - as you can imagine, that is an expensive way of doing so not recommended !

So while don't really like saying in Bob - that is what you are going to have to do as above - wait until the fault manifests itself more so - at which point, the dash will tell you and again - that then is the time to have the plug in tests done ...and you are there then!

There really is no need for worry meantime - you have had all the brakes checked out so no worries there - so thats the way forward now on this one Bob.. Im sorry I can't be more specific - but I hope you can see why from the above -

Let me know how you get on if you wish- or if you need anything else at all.

Kind Rgds - MIKE.

...Meantime..............Please do click on the "OK/ Excellent ratings" for me as that's how Im credited for helping you - Thank you in advance for that...

You can and are most welcome to get back to me anytime you might need - clicking the OK ratings does not close you out at all..

Rgds, MIKE.
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