ABS&ESP light S4 2004

[Ian891]

Hey would love some advice 

I have a 2004 4.2 V8 S4 - 

I have an issue where my ESP & ABS light came on intermittently becoming more and more consistently on. 

Things I have checked and replaced 

Wheel sensors, reluctor ring, ABS control unit but the lights are still on - everything works but this is a real pain - anyone had this issue and does anyone have any advice 
I was informed brake pedal switch which I have not tried yet ... any assistance massively appreciated 

Thanks 

[Steve Q]

Could be a brake pedal switch. Alternatively get an auto electrician to check the wiring for the system. 

[cliffcoggin]

Ian.

You have two identical topics running in separate forums which are both attracting replies. Please delete one or the other to avoid any confusion. Let me know if you can not do that and I shall sort it out somehow.

[Ian891]

Hi Cliff 

I posted on both forums as essentially the B7 was a facelift for the B6 the 4.2 V8 engine is exactly the same yet there will be owners on both forums and as I am struggling with a solution I wanted to ask both owners of the B7 & the B6 - it would be good if the forum actually broke down the models so S4 owners from 2001 - 2008 would cover this off! 

Thanks 

[Magnet]

Thanks Ian, 

Have you viewed and responded to the posts on the other section? 
Kind regards,

Gareth. 

[Magnet]

Any comments for us Ian? 

[Ian891]

On 12/5/2024 at 8:48 PM, Magnet said:

Thanks Ian, 

Have you viewed and responded to the posts on the other section? 
Kind regards,

Gareth. 

have responded to all messages 

[Ian891]

On 12/5/2024 at 2:33 PM, Steve Q said:

Could be a brake pedal switch. Alternatively get an auto electrician to check the wiring for the system. 

Brake pedal switch not the issue - changed this and still fault appears - I am guessing it is going to be a wiring issue 

[Ian891]

On 12/5/2024 at 2:33 PM, Steve Q said:

Could be a brake pedal switch. Alternatively get an auto electrician to check the wiring for the system. 

Thanks I think its a wiring issue as brake pedal switch was replaced and fault remained .....

[Magnet]

Thanks Ian,

When you say you changed a recluctor ring, was that on the wheel which is showing the fault on diagnostics? 
Kind regards,

Gareth. 

[Ian891]

Hi yes brake pedal switch changed, wheel sensor changed reluctor ring changed ABS control unit checks carried out all showing no issues but fault is being sent to dashboard so am guessing its a wiring issue... 

Whilst doing this I have also changed all the pulleys tensioners and belts as I did not do these when I had the timing chain done. 

in the last year I have replaced 

Timing chain 

Valve cover gaskets 

Oil filter gaskets and oil and filters twice! (like the engine to have clean good oil depsite the car on doing less than 2000 miles this year!)

Front suspension fully 

discs & pads all corners 

new pilot sports on al corners 

all rear light cluster wiring looms 

speed sensors reluctor rings 

all soft touch controls in !Removed! pit 

new headlights - bugger to find 

as well as the engine being completely serviced and in immaculate condition

once I sort this stupid ABS ESP light issue the car will be faultless but this is a real pain to diagnose!!

[Steve Q]

5 hours ago, Ian891 said:

Brake pedal switch not the issue - changed this and still fault appears - I am guessing it is going to be a wiring issue 

Keep us posted on how you get on with an auto electrician 

[Magnet]

Thanks again Ian, but I’m still unclear on which wheel the new Reluctor ring was fitted to - sorry if I’ve missed your answer to that question. 

[Ian891]

The one that the wheel sensor displays the fault on 

[Ian891]

6 hours ago, Magnet said:

Thanks Ian,

When you say you changed a recluctor ring, was that on the wheel which is showing the fault on diagnostics? 
Kind regards,

Gareth. 

Yes it was! 

[Magnet]

OK Ian, we are only trying to get the written fact that will help us to help you, so the ! really is surplus to requirements. 
Moving forward:- 

Run diagnostics again to confirm that the front wheel is still the only offender.

If so, check and trace wiring to sensor. Incidentally, what make sensor/s did you buy, and did you fit 4 of them? 
If wiring traces OK, consider other options such as rear wheel ‘senders’ which are built into the hubs. 
Finally Ian, we are not the Spanish Inquisition, but we do need facts to help, and being helpful is our only aim. 
Please come back to us with what you think.

Kind regards,

Gareth. 

[Ian891]

Hi used OEM sensors from Audi 

just did the from ones - the fault code still states front right sensor failure so I’m having the wiring traces checked 

hopefully this will resolve if so will update! 
no worries on the questions at all really appreciate any input in trying to resolve! 

[Magnet]

Thanks Ian,

Have you got your exclamation button automatically logged in by any chance? 

[Ian891]

😁