[ant68]

Hi, I hope someone can give me some insight into this issue.

We have a 2002 Mercedes-Benz C320. Some time ago the brake wear sensor came on, and after looking at the brake pads, it was time to replace them. We bought original MB brake pads (front and rear) along with new brake wear sensors and we left our car at our regular mechanic to replace the pads, install the wear sensors, resurface the discs.

But then, ever since the work was done, the ESP (Electr. Stabilization.) plus the BAS (Brake Assist) warning come on, goes off for 2-3 seconds, and then the 2 warnings, plus the ABS light stays on until the next time we start the car. Other than that, the car seems fine and brakes normally.

I don't know if the ESP/BAS warnings came on as a result of replacing the pads or it is a separate issue. I'm assuming it's just a coincidence that it happened at the same time, and it's not related to the brake pad replacement.

I did some research on the forums and this is what I tried so far:

• I removed all 4 wheels and rechecked the mechanic's work, and I didn't see anything out of the ordinary or incorrectly; everything looks normal (I've replaced the brake pads & wear sensors myself 5 years, so I know how things are supposed to look like).
• I've done the ESP reset, turning the steering wheel all the way to the left, then all the way to the right, and then centering; tried all combinations of turning the steering wheel. That didn't make either the ESP or the BAS warnings go away.
• Checked the brake fluid to make sure it was in the range.
• I had autozone check the battery to make sure it was not a drop in battery voltage triggering it.
• Next, I was going to replace the Stop Lamp Switch / Brake Light Switch. Now, here's what puzzles me.

I looked over the instructions I found on the forum that whenever the ESP/BAS light comes on, it's usually because the Stop Lamp Switch (official mercedes name for it, but some call it the Brake Light Switch) is bad or needs adjusting. Following the instructions, I remove the panel under the driver's side dash, then the plastic piece covering part of the brake pedal, followed the path of the brake pedal as far up as I can, and I don't see any Stop Lamp Switch.

I expected to see something that looked like this:
Amazon.com: OES Genuine Stop Light Switch: Automotive

But there is nothing like that. I can see a "spot" where I think the switch would be at, there is a small arm with a hole where I picture this switch fitting in, in such a way where the "plunger" on the switch would be pressed/released by the brake pedal arm. But there is nothing there. No Stop Lamp Switch at all.

Also, this is a trusted mechanic who has worked on this car and our Camry several times before, and I doubt he would have removed the panel just to remove the switch. In addition, I don't see any disconnected wires that would have been connected to the switch.

Another piece of information to add: I went to the local Mercedes dealer to buy the switch, and when entering our VIN, their computer doesn't show a Brake Light Switch for him to pull from stock. Puzzled, he went to the back, then brought the switch (which looks the same as the one in the Amazon.Com picture), showed it to me, and asked me to make sure that our mercedes has this part before I purchase it; the part is about $31.

My question is: Did the 2002 C320 model stop using the Stop Lamp/Brake Light Switch and it was combined with some other another sensor?

Or was there a technical bulletin where previously this particular year did not have a switch, but now we are supposed to install a switch? And if so, which existing set of wire would I have to unhook, to hook up to the switch?

Puzzled... Any insight is appreciated. Thanks!

 

[2002c230]

How's the alignment? If it's off to a certain extent the ESP/BAS message will display. Happened on my 02' Sportcoupe. Most likely cause is a damaged wheel speed sensor. It's an easy sensor to break if you're doing brakes...

 

[shauns]

Hi, I have a 2002 S280 and shortly after I got it, I needed to get a new wheel bearing installed on the front. Driving out of the garage, the abs light came on, then the esp light, then the BAS. I didn't wait for anymore, turned right around and drove straight back into the workshop.

Following morning got a call and was surprised to be told that the source of the problem had been down to some grease covering the a few of the perforations on the perforated abs disc when the bearing was fitted. Try checking this disk on your own car in case one has been contaminated or obstructed which in turn can cause spurious messages to appear

Hope this helps

 

[rudeney]

The primary symptom of a failed brake pedal switch is the shifter interlock not releasing. If that works, the it's likely something else triggering the fault. As for the switch, there is one, but I believe it was moved to other side of the firewall, near the master cylinder, but I didn't think that happened until the MY2005 update.

 

[josephmg50]

Hi, I have a 2002 S280 and shortly after I got it, I needed to get a new wheel bearing installed on the front. Driving out of the garage, the abs light came on, then the esp light, then the BAS. I didn't wait for anymore, turned right around and drove straight back into the workshop.

Following morning got a call and was surprised to be told that the source of the problem had been down to some grease covering the a few of the perforations on the perforated abs disc when the bearing was fitted. Try checking this disk on your own car in case one has been contaminated or obstructed which in turn can cause spurious messages to appear

Hope this helps

I am following along here as I am having he same type issue with my 2002 C320 also. My issue seems to be cold weather related and when the ESP/BAS warning arise, I can take vehicle to an icy/snowy patch and heavily apply brakes to activate the ABS and, VIOLA, warnings go away for a small period of time.

That said, I have replaced the brakes a few months ago and not had the issue as well as the front wheel bearings - no issue until the cold weather. Question is now after reading the "grease covering the perforations" item, where exactly is the ABS disc described? Curiousity is now making me think this is coved or blocked by some ice build up possibly but not 100% sure where to look?

Any input would be great