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991 brake light switch

joristz750

New member
Joined
30 Nov 2018
Messages
2
hello,
I am new here. Live in Belgium an I have a 991 S.
after 92000 km, I have my first issue with my car. The brake light switch was not working properly and I got the warning that the PSM was put out of order. ( also start/stop) My Porsche Centre cleaned the switch ( don't know how) and the system worked again. Now, after 10 months, again the same problem. My local Porsche mechanic changed the switch with a new one. After 1 month, the same problem... I am getting nervous about this and I wonder if there might be another cause then the switch itself. Is this problem familiar to someone? Many thanks for your input. Cheers Joris.
 
Difficult to give you an answer but i will say .. is there any chance you rest your foot under the pedal when driving .. is it possible you have in some way pulled the pedal upwards basically .

The switch is an air gap sensor .. magnetic i belive .. there is no rod touching the pedal and as such the distance between the sensor and the pedal needs to be exact .

Thats about all i can say as everything else means inspecting the car and looking at fault codes .
 
Hello
indeed, it is a "hall" sensor ( magnet).
Point is that I have the car for 5 years now, and never had a problem before. In one year time, I had 3 issues with this switch. And the reading of the computer tells ... the switch has a fault.
DSC-7909.jpg


the switch costs 32 euro, so it's nothing much about.
 
The lack of moving parts should mean this part lasts for a long time .. the only problem i have ever come across with these is when the gap is altered.


I am however starting to wonder about a wiring fault , i dont have the topoligy at home (list of the control units and what sensors go where ) but i would expect the signal would goto the steering column CU and then a can/Lin bus message to the PSM.

It would be worth checking actual values and maybe a pin out of the wiring to check for resistance if this fault continues .
 

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