ASR / BAS light - '98 E300TD W210 - PeachParts Mercedes-Benz Forum

dukegrad98 · #1 04-22-2007, 10:06 PM

I've done the searches, and it looks like the brake pedal switch is the most common cause of the BAS light coming on the dash. But I'd appreciate a few opinions as a newbie to Benz. I've put about 2000 miles on this car, which has a total around 174,250. The number 2 glow plug is bad, and I haven't gotten around to replacing it yet, but the car has been running fine aside from that MIL.

Tonight, the ASR light came on. As soon as I hit clear to get the dash back to normal, the BAS light came on. After reading about possible problems (such as low voltage), I went out for another drive. My OBD-II scanner shows no code for this -- perhaps because the scanner is too cheap, or perhaps because the BAS/ASR light is not engine related. I have no idea.

The brake lights still work, both when the light is glowing and when it is not. The light resets when I turn off the car and restart, but it seems to be coming back on consistently during driving. However, there is no correlation to it coming on when I brake -- sometimes I'm braking and sometimes I'm not, but either way the light comes on. That makes me think it's not the switch, but...maybe it's stuck?

I read that low voltage may cause this also. In diagnostic mode (using the climate controls), I get a steady 13.5 volts, plus or minus .2 while driving. When the car is off, before ignition, the battery reads out about 11.5 volts while the glowplugs heat. During cranking, voltage dips for a split second to about 8.5 volts, then rebounds almost instantly to 13.5 as the engine starts. Starting is no problem.

So...anyone want to give me some tips? I know my way around cars but am new to Benz, and am not anxious to pay the labor rates that people seem to put on these cars!

Many thanks --
Cheers, John

dukegrad98 · #2 04-22-2007, 10:19 PM

I should clarify... The digital readout is what was giving me the ASR error, followed by the BAS error. This is the center section of the dash, where I usually have an odometer, etc. The actual ASR/BAS/ESC or whatever it is light on the left side of the dash stays lit continuously, and does not clear when I hit the "R" button to get back to my odo readout. Thanks again.

Cheers, John

Matt L · #3 04-22-2007, 10:35 PM

You need the Star diagnostic tool to check the codes for this. I'm pretty sure that only engine codes are available at the OBD-II port under the dash, as required by US law. The rest are available at the port in the under-hood fuse box. The Star diagnostic tool isn't just more expensive than what you have (or what I have). It's obscenely expensive. Something like 3k/year for the license fee for the software, plus the outlay for the hardware.

My climate control unit usually also shows about 13.5, but the actual voltage at the battery is a bit higher at around 14V. Check yours with a voltmeter to ensure that yours is also higher than 13.5V, which really is a minimum charging voltage (but should be fine).

The brake switch can cause problems that occur when you hit don't the pedal. If it were mine, I'd probably change this part, for what it costs. Be sure to get the M-B part for this.

Parrot of Doom · #4 04-23-2007, 06:51 AM

Try moving the steering from lock to lock. That may be a solution to a different problem, I can't quite remember.

dukegrad98 · #5 04-24-2007, 02:24 PM

Thanks for the info, guys. The light still comes on intermittently, so I'll try to get by the dealership later this week and buy a switch. Anyone know the part number offhand? I've seen it on these forums for the ML-class, but I don't remember seeing it for the E300TD. If nobody knows, I'll just harass the service guy into looking it up for me. Will be a weekend project to get under the dash and install it, I suppose...hope it fixes things!

Cheers, John

BENZ-LGB · #6 04-24-2007, 03:24 PM

Odds are that it is the brake switch. My 98 E320 just went through it.

The brake lights still work fine. What won't work is the Brake Assist System and the ASR (I forget what the letters stand for). You won't notice it, unless, of course, you have to make an emergency, panic stop.

There are plenty of links showing how to replace the switch. If not here, try Benz World or the MBCA website. It is a fairly easy job.

I had my mechanic do it while the car was in for an oil change.

Good luck.

BTW...I would love to get my hands on a nice W210 diesel wagon.

dukegrad98 · #7 04-26-2007, 05:22 PM

Alright, brake light switch has been replaced - dealer charged me $17 for the part, which seemed plenty fair.

The intermittent dummy light has stayed out for 40 miles on the road so far.

However, the brake lights are constantly lit now, whether I'm pressing the brake pedal or not. Not good! Any ideas? See this thread:
http://www.peachparts.com/shopforum/tech-help/186598-w210-brake-light-switch-replacement.html#post1491333

Thanks!
Cheers, John

dukegrad98 · #8 04-26-2007, 05:55 PM

PROBLEM SOLVED. The self-adjusting switch needed to have the plunger pulled all the way out before being installed. Thanks to slk230red for pointing me in the right direction. The brake lights are now operating properly. I will update again if necessary -- for now the dummy lights are out, and I'm assuming all is well. Thanks to everyone for the tips.

Cheers, John

BENZ-LGB · #9 04-26-2007, 06:37 PM

Quote:

Originally Posted by dukegrad98

PROBLEM SOLVED. The self-adjusting switch needed to have the plunger pulled all the way out before being installed. Thanks to slk230red for pointing me in the right direction. The brake lights are now operating properly. I will update again if necessary -- for now the dummy lights are out, and I'm assuming all is well. Thanks to everyone for the tips.

Cheers, John

You'd have thought that the tech at the dealer would: (a) know about the plunger and (b) road tested the car to see that it was working correctly. Oh well!

How much time did the dealer charge for labor?

dukegrad98 · #10 04-26-2007, 06:40 PM

I did the labor myself -- just bought the switch from the dealer. The plunger was all the way in, and I doubt the guy in the suit at the parts counter had a clue how to install it. I didn't talk to a real tech or anything -- relied on the good folks here.

I can't blame the dealership for any of this...it just never occurred to me that a brand new switch would need to be manipulated prior to installation.

Putting the switch in the first time only took about 25 minutes. It took me longer to get the under-dash plastic panel off than to change the switch itself. Then after the "malfunction," I was in and out of the car again in 10 minutes to get the switch working properly.

Cheers, John

BENZ-LGB · #11 04-26-2007, 07:19 PM

OK..got it. I thought you had taken it to the dealer for the actual install.

Well, then you have no one to blame but yourself!

Thanks for sharing the info.

Hirnbeiss · #12 05-01-2007, 05:55 AM

I just did this R&R on my machine which is coming up to 100K now. The light had been coming on occasionally over the past 10K+ miles, but decided this weekend that it wanted to illuminate my life permanently.
Anyway, I disassembled the nad switch to see what was what, and there were two small squares - like flakes- of copper broken off of one of the contacts. It's very thin, and looks like it's doomed to a fatigue failure at some point. Anyway, no chance of a simple clean-up and re-install.
I took 2 pictures, but the background is mottled so you can't even see the flakes.