just got a 2004 A4. for some reason the cruise control wont turn on. also, when im on the highway, the EDS light comes on after about 10 min of driving. any ideas? might the problem be linked?

did a scan with vagcom, this is the only noteworthy faultcode that came up

1 Fault Found:
16955 - Brake Switch (F): Implausible Signal
P0571 - 008 - Implausible Signal - Intermittent

i also noticed today that the brake lights stay solid all the time.... cant be safe for driving if the person behind me always thinks im braking......

 

any ideas?

 

need to get this figured out!

 

Obvious question: have you pulled the cruise control stalk one click towards you before trying to set the cruising speed?

You car's an '04, so it's still under warranty. Why not take'er to your preferred dealership to have this looked at?

 

I will look at it tonight, did you try clearing the fault codes with the vag-com? have you checked all your fusing?

 

cleared all fault codes. the cruise worked after the first fault code clearing ONCE, then stopped working again. the only code that came up again was the breake one listed.

my car just came out of warranty in march

i will check the fuse after work today. cross my fingers its something that simple....

 

Ill check the wiring diagrams once i get home and check the fault code I will let you know tonight

 

awesome, thanks for the help!

 

Check switch
Remove driver's storage compartment:
Disconnect connector from Brake Light Switch -F- / Brake Pedal Switch -F47- -2-.
Connect multimeter between terminals 1 and 4 to measure resistance.
Specified value: ∞ Ω (no continuity)
Press brake pedal.
Specified value: approx. 0 Ω
Connect multimeter between terminals 2 and 3 to measure resistance.
Specified value: approx. 0 Ω
Press brake pedal.
Specified value: ∞ Ω (no continuity)
If the specified values are not obtained:
Replace Brake Light Switch -F- / Brake Pedal Switch -F47-.
=> Repair Manual, Brake System; Repair Group 46
If specifications are obtained:
Check power supply
Connect voltage tester V.A.G 1527 B as follows:
Connector

terminal
Measure to

1
Vehicle body ground (GND) point

LED must light up.
Connector

terminal
Measure to

3
Vehicle body ground (GND) point

Switch ignition on.
LED must light up.
If LED does not light up:
Check wiring for open circuit and repair if needed.
If LED lights up:
Check activation
Check for open circuit and short to positive or ground (GND) in following wiring connections:

 

The brake switch is definitely the culprit. It's a cheap fix to swap it out. It's just a little microswitch located at the top of the brake pedal.