W202 C220 CDi - BAS ESP

[420SE]

Pootling along today and the BAS ESP light began to light up.

I have done some research and it states that the light will ignite if there is an issue with the brake assist system.

Anybody else has this issue? An expensive fix?

This is exactly why I need to hurry up and order a scanner, so that I can read the fault codes. The light simply tells me that there is an issue with the brakes, but hopefully the scanner will tell me a little more than that.

 

[renault12ts]

Brake light switch...most likely.

 

[420SE]

I noticed something else too...

1. When the light switched on, I could not engage cruise control.

2. I got home, left the car to stand for 20 minutes outside, jumped back in to take it around the block and the light is nowhere to be seen.

3. This is the 2nd / 3rd time the light has come on. The car is mainly used for longer journeys of 20 miles+ due to its rather reasonable MPG and the light would typically come on about an hour into the journey.

Any more thoughts?

 

[renault12ts]

Or a brake sensor, or exciter ring problem.

 

[420SE]

Any idea on the cost of a replacement

(a) brake light switch
(b) brake sensor

 

[renault12ts]

Switch...cheap, sensor...£90ish.

 

[420SE]

Thanks

I have done a detailed search / read of the forum and it could be any one of these:

- fault with a relay on the ESP BAS system inside the relay fuse box. There’s another relay of the same type in the relay box, so worth swapping them over to see if fault persists

- brake light switch

- wheels speed sensor

- lateral acceleration sensor

- steering angle sensor

- sensor on servo

- plug contacts dirty? Perhaps worth cleaning the electrical connections to the ABS unit, and covering the ABS unit with a plastic bag to keep crap off the connector

Will take it to a garage near me tomorrow, they aren't MB specialists, but maybe they have a fault code reader they can hook the car up to.