Additional switch on the Brake Pedal to Start the RS3

RS03???

Registered User
My daughter's car is going to Audi as over the last week, she has to practically have to stand on the Brake pedal to use the push button to start the car...... Seems overnight the brake loses the vacuum and the peddle is rock solid. No problem, if the car has been recently used (within a few hours).
Brake lights come on, but the car will not start, until Brake pedal is pressed hard.
Wonder, if its another electrical switch on the brake pedal or pressure switch on the brake hydraulics.
Audi call-out man said its a common issue on many Audi's.. :culpability:
 
Last edited:

T-1000

Well-Known Member
Gold Supporter
My daughter's car is going to Audi as over the last week, she has to practically have to stand on the Brake pedal to use the push button to start the car...... Seems overnight the brake loses the vacuum and the peddle is rock solid. No problem, if the car has been recently used (within a few hours).
Brake lights come on, but the car will not start, until Brake pedal is pressed hard.
Wonder, if its another electrical switch on the brake pedal or pressure switch on the brake hydraulics.
Audi call-out man said its a common issue on many Audi's.. :culpability:

Brake light switch on the servo (item 7)
Nothing showing on the actual pedal mechanism though.
477794cdfddfc3a18ff8cb30f6bbd4ab.jpg



Pedal

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RS03???

Registered User
Thanks, Switch on the master cylinder.. and a single switch. Must be the same operations on the brake pedal type on the S5.. have to wait on what Audi find this Friday as to why loss or vacuum in the brake system, impacts the ability to crank the car.
 

T-1000

Well-Known Member
Gold Supporter
Thanks, Switch on the master cylinder.. and a single switch. Must be the same operations on the brake pedal type on the S5.. have to wait on what Audi find this Friday as to why loss or vacuum in the brake system, impacts the ability to crank the car.

Only time I've experienced the hard brake pedal is after repeated pressing of it when moving the car forwards/backwards in the garage without starting it up, but this is only because the servo assistance becomes depleted.
 

T-1000

Well-Known Member
Gold Supporter
Thanks, Switch on the master cylinder.. and a single switch. Must be the same operations on the brake pedal type on the S5.. have to wait on what Audi find this Friday as to why loss or vacuum in the brake system, impacts the ability to crank the car.

Only time I've experienced the hard brake pedal is after repeated pressing of it when moving the car forwards/backwards in the garage without starting it up, but this is only because the servo assistance becomes depleted.
 

RS03???

Registered User
exactly, that how we reproduced the lack of cranking, without standing on the pedal. As she had it from new, she noticed the change immediately from one morning to following morning. Mobile Audi Assist, said to book it in. Strange, brake lights come on, but does not crank until all of her leg muscle is pushing really hard on the brakes with her 50Kg frame.
 

deepy

Registered User
Does your daughters car have AWG fitted ? as I've experienced a similar thing on mine after entering the code and pressing the start button.
 

deepy

Registered User
Does your daughters car have AWG fitted ? as I've experienced a similar thing on mine after entering the code and pressing the start button.
 

RS03???

Registered User
Nothing additional after market device fitted except a smelly/perfume card.
AWG = some sort of anti theft device ?
 

RS03???

Registered User
No Ghost or similar... Thanks..

too many 3 letter abbreviations..
I remember AWG = American Wire Gauge from my head.
 

stuart scott

Registered User
Has this been resolved yet as i have the same problem,i only got the car on Saturday its a 2018 s4 with 22000 miles the dealers have put new pads and disc’s on the front i wonder if that has anything to do with the fault
 

RS03???

Registered User
No, All Diags check out, no fault found, even though the audi assist technician stated its a known issue with servo vacuum being lost over night. The car is 2019, 8000 miles, driven with a light foot. Just have to monitor for a pattern. Not pleased with the zero outcome.
 

garethdj

Active Member
Not long had an RS3 and just joined the forum. I've noticed this for the first time today. Will report back if it reoccurs.

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RS03???

Registered User
Not long had an RS3 and just joined the forum. I've noticed this for the first time today. Will report back if it reoccurs.

Sent from my VOG-L29 using Tapatalk
Hope it does not repeat.
 

garethdj

Active Member
I've noticed it does stiffen up sometimes but not to the point where I feel it's an issue. The car is sat on the drive all through the week at the minute.

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RS03???

Registered User
I've yet to notice it yet on mine... The Vacuum is being lost on my daughter's faster as the car gets older.. (2 years now)
 
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