Cause: order of likelyhood.

Faulty Brake light switch. 2 circuits.
Faulty / dirty speed sensor wire. usually front.
faulty speed sensor connector. corrosion/water
Incorrect tyre size or differential tyre wear.

Bazzle could be spot on.

 

Not the most common cause BUT Bazzle could be spot on.
Stuart

 

I also have a 99 slk and the BAS/ASR came on the other day. I think its because i had put 3 pizza boxes on the passenger seats. I don't know if this is of any help to you but mine just went away when i shut off the car and restarted it.

Good Luck!

 

I just went through this on my 2001 SLK230. The BAS/ESP light would come on when I put my foot on the brake pedal and my brake lights wouldn't work. I reset the brake stop switch at the brake pedal and that fixed the problem. I went directly to the dealer and purchased a new brake stop switch and replaced it.

Dave

 

Hello,

I have a 1998 SLK230 (automatic). Few days ago I noticed that the ASR warning light came on (only the warning, not the Hazard triangle light). After lot of reading, I tested a few things.
After starting the engine the ASR is off. After a few minutes of driving ASR light comes on. If I manage to drive without braking (hand brake and luck...), the ASR wont come on.
And when I start using the brake, after a few brakes, the light comes on when "releasing" the brake.
I also tested this, without moving the car. After starting the car, keeping the hand break take the car our of P, and press the brake pedal a few times.
In a few tests, I noticed that the ASR comes on no matter if the gear is in P or D.

I didn't see any issues with the break light.
Now, .. I am thinking, that since the car is not moving, likely it is not the speed sensor. (Hall effect sensor).

Based no these tests, can we conclude that very likely it is the brake switch ?

How difficult is changing this switch? I have already opened up the plastic trims before (for chaning the bulbs behind cluster). Is the switch easily accessible near the pedal? any tools needed?

Thanks

Kaveh

 

problem solved,...
all summarized in:

http://kaveh.afshari.googlepages.com/slk230asrdebugging

 

Jeff,

ESP/BAS light used to come on now and then fo no reson, but usually when the engine was cold. Mercedes has changed the speed sensor and the problemseems to be gone.

Robert

 

Robert,

There are several speed sensors.
Usually the cause is that they get "dirty" with brake rotor and pad debris which sticks to the tip.
Maybe they just needed cleaning but glad the issue has now been resolved.
As I have posted previously the Top Hit for this problem is a failing Brake Light Switch with dirty / damaged / faulty Speed Sensors No. 2 in that order.

Stuart.

 

Reading through these replies, I am wondering if the same remedies apply to my 91, 560 SEL which also has an ABS light that sometimes comes on, and the ASR light which is always on, but only after a couple of minutes driving. Even so, the triangle light comes on if I make the car skid, showing that ASR works, all very confusing.

 

Hi,

The ASR (triangle light) works when the ASR malfunction light is illuminated?

The malfunction light comes on ONLY after driving some distance rather than at ignition on + X seconds. Correct?

Mmm?