2011 A6 C7 with ESP and EPC warning light

PetrolDave

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In other words you are saying the brake light switch is bad?
If the wiring is all correct between the switch and the ECU that's what I'm thinking is most likely - but one last suggestion, if possible disconnect only the 'signal wire' from the switch and measure what happens on that pin of the switch when you operate the brake pedal - if it switches between 0V and 12V then the switch is OK.
 
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coconutaudi

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Thank you guys. My problem is solved. I replaced the new brake light switch with another new one. When I pressed the ignition on, the ESP warning light immediately disappeared. After a one hour drive neither the ESP nor the EPC came back. I think it’s a fix. VCDS has correctly diagnosed the problem but a faulty new part had delayed the fix. This thing can happened and throw us off track. One thing I’ve noticed is that the brake switch test on the latest brake light switch still shows the last zero changed to 1 instead of the expected last 2 zeros changed to 11 as pointed out by Crasher. I think maybe it is because my car is an older generation which used only 3 out of the 4 available pins on the brake switch. I tried to post some pictures here but failed. I used Imgur but the picture link just won’t load. Any way thanks to you guys for the help. Really appreciate it.
 

PetrolDave

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Thank you guys. My problem is solved. I replaced the new brake light switch with another new one.
Where did you purchase the original 'new' switch? Are you 100% certain it was a genuine part and not a Chinese Replacement Auto Part?
 
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coconutaudi

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Where did you purchase the original 'new' switch? Are you 100% certain it was a genuine part and not a Chinese Replacement Auto Part?
It’s an original Audi part. I’m very sure of it because I bought it from my regular vw/audi parts seller. The seller replaced the faulty unit after much persuasion as he initially didn’t believe me that the brake light switch was defective. It’s definitely not a CRAP.
 

EuroX

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If it wasnt purchased at the dealer or a reputable parts vendor the switch and parts are just that... SHIT.
 
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