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Discussion Starter #1
Hi guys getting a code for vacuum pump 17837 open circuit
connection looks good , car brakes fine ...
do I need to replace thisnpump or can I leave it like this ,
thanks
Erick
 

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Brake Booster Control Module (J542)


If you are using vcds; there maybe output teats, you could try.
 

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Good question: correct brake operation; is not something to ignore; testing, would be next to find the problem? Brake failure or reduced performance; could put your life on the line, i would fix the problem correctly.


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Good question: correct brake operation; is not something to ignore; testing, would be next to find the problem? Brake failure or reduced performance; could put your life on the line, i would fix the problem correctly.


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Your life and other lives. Those riding with you and those sharing the road with you.
 

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Discussion Starter #9
For sure I would not risk . Was just wondering since I read there is a lot to délesté it on the 2,5 and the brakes feel fine .
 

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The ross tech trouble code; mentions the J542 vacuum pump; here is a self study program, that might apply to your unit and explain how it works:

Self-Study Programme 257
Electric vacuum pump for brake servo unit
Design and Function


The SSP; states the purpose of the pump and why it is needed:

Cars fitted with a petrol engine in combination with an automatic gearbox which comply with the EU 4 Standard have an electric vacuum pump. This is used for assisting the brake servo unit. In this engine-gearbox combination, the throttle valve is opened particularly wide when the engine is started from cold, as well as when it is idling with a drive position engaged and the brakes applied. This is intended to reduce the pressure drop in intake manifold.


Discussion of trouble code and testing info on a 1.8T automatic Jetta:



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Discussion Starter #12
I was just curious , I would never gamble with safety . Was just curious on how useful it is since it’s broken and I would have never known unless I scanned the car
 

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VW put it there for a reason and it is part of the brake system. Download and read the #257 self study program; which explains its function and why it is installed. It sounds like in certain circumstances; the pump, helps with low vacuum, in certain scenarios, which can impact brake performance. The testing procedures; will help you diagnose the problem (fuses, wiring, possible component failure; which requires assembly replacement).
 

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Discussion Starter #14
Trying to find that elusive fuse 51 ??
checked under the dash etc..
1-Anyone know where it is on a 04?
2- trying my best to diagnose , no power to the pump ground is good
Anyone have a wiring diagram for that section I really need to find where the power is coming from
Thanks
 

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Discussion Starter #15
ok guys found the fuse 51. its under the driver dash way on top well hidden , it was a 15a but I think I should have beed a 20.
the pump was seized and burnt the fuse .
 
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