E430 ESP/BAS problem - PeachParts Mercedes-Benz Forum

vince · #1 10-07-2004, 03:20 PM

1999 E430. The "ESP" warning came on in the Malfunction Indicator while traveling a straight section of highway at 60 mph. The "multiple malfunction" indicator (looks like two pages super-imposed on each other) came on also. The "ESP Warning Triangle" in the speedometer did not illuminate. The ESP switch on the console did not work. When I shut the key off (for a gas stop) the "BAS" warning came on in the Malfunction Indicator. When I restarted the car both had cleared. In the recent past the "ESP Warning Triangle" in the speedometer dial had come on briefly when making turns at moderate speeds (25-35 mph) in normal, not aggressive driving, on dry surfaces. Also, the "ESP Warning Triangle" in the speedometer dial had come on, and what sounded like the ABS system activated, during a turn in a cul-de-sac under the same seemingly ideal conditions. It seems as if the threshold for ESP intervention has somehow become too low. My dealer says the brake booster is at fault. Does this seem logical? I do not have any codes yet.

Arthur Dalton · #2 10-07-2004, 03:27 PM

Check all tires for equal air pressure...
If all is well, the most common fail part is the brake lamp switch..

blackmercedes · #3 10-07-2004, 04:25 PM

I understand the rear ABS sensor on the final drive unit can also fail giving ESP fits. I have never heard of a fault brake booster, anyone else?

suginami · #4 10-07-2004, 04:49 PM

The ESP lamp went off in my mother's E430.

I checked her owner's manual, and it said that is voltage goes below a certain level, the lamp will be illuminated.

The fix was to turn the steering wheel from left to right so that the system could "relearn", or something to that effect.

MB STARS · #5 10-07-2004, 05:27 PM

Go have code read see what codes in your BAS,ESP control unit ??? it will help you to diagnosis the system.

azinn · #6 10-07-2004, 07:07 PM

Quote:

Originally Posted by Arthur Dalton

Check all tires for equal air pressure...
If all is well, the most common fail part is the brake lamp switch..

Yes the brake switch is a very common problem on the M Class also, check this http://forums.mbnz.org/forums/forums/thread-view.asp?tid=1166641&posts=14&hl=brake+switch out.

Gilly · #7 10-07-2004, 08:57 PM

Don't know why the dealer would fault the booster without a proper diagnosis (or have they diagnosed it). But yes to answer John's question, there is a part in the booster for the BAS system which isn't available seperately, so it could need a brake booster because of this. I believe it's called the diaphragm travel sensor, could be wrong, maybe MB Stars will know for sure. There is one sensor which IS available seperately and one that isn't. (PS: Of course the one that IS available seperately I've never seen fail

)
Sight unseen I'd more lean on the brake switch too, common on the 163, MORE common on the 210 it seems like. If it does this again if at all possible make SURE the brake lights are working. There are 2 sets of contacts and depending on which set fail you may not have operating brake lights, If EITHER set fail you'll get these warnings on the dash though. So you can get the warnings and may or may not have operating brake lights, so use caution.

Gilly

MB STARS · #8 10-07-2004, 11:37 PM

Yes we have replace few of brake diaphragm travel sensor (control unit have to know how far the brake booster diaphargm travels)on 163 or 210 but also brake light switch is very common problems,the correct way dignosis BAS,ESP is read the code first then go after each code watch live data of the system to find out witch sensor cause problem today cars you must have the right tool to dignosis you can't compare 2004 car to 1994 car Mercede make a jiant step in ten years,just like your cell phone think about the cell phone you have ten years ago and the one you have right now what a different( phone E-mail,message,photo,on-line,sport news,weather,GPS,ring tone.......) by the way the travel sensor is available seperately. hope this help.

vince · #9 10-08-2004, 08:07 AM

Thanks for the help. This is what the dealer says: "Brake booster pressure switch short test performed - code C1406. Electrical system check/det condition - found brake booster pressure switch intermittantly open." They replaced the booster and a couple of ancilliary parts (not the travel sensor, though). Which brings me back to my question - does this make sense? I am just trying to understand the interface between the ESP and BAS systems and make sure that whatever the problem, it gets fixed right before my extended warranty expires next month. Also, maybe this thread will benefit someone else down the road. I did flog the car after I picked it up and it seems OK. But, the problem was intermittant, so who knows. Incidently, I had checked tire pressures, they were spot on. I checked the battery voltage and it was fine. I did not check the brake lights.

Gilly · #10 10-08-2004, 09:27 PM

Yes this makes sense. The ESP and BAS are both brake related systems. If you get a code in either one of these systems it'll start throwing warning lights for both systems, even though in this case it was only a BAS fault. I guess they figure if the BAS system is compromised that the ESP system is compromised also.
I thought the "pressure switch" was the replaceable component, but I could certainly be wrong on that.

Gilly

ps Now that I think of it, I don't remember that when I had to replace a booster that I had to transfer one of the switches onto the new booster. Hmmmmmm

vince · #11 01-28-2005, 05:37 PM

Today the BAS & ESP lamps came on again. The car has 673 miles since the dealer put in the brake booster (that was October 7, 2004 - I don't drive the car that much - obviously). Despite the general agreement that their diagnosis might make sense, I have had a nagging doubt. That doubt is now confirmed.

I had been driving the car on some short trips and after a short stop the BAS lamp came on then the ESP lamp. The BAS lamp came on just at the end of the start cycle. The BAS lamp remained on for a minute or so after I shut down for my next stop. When I restarted the car after two minutes or so, both lamps had cleared. I don't have the ability to read the codes. The code last time, as can be seen above, was ESP C1406. Of course, the extended warranty expired in the months that have ensued, so this is on my nickel and I would really like to fix it right.

Any ideas? I am guessing anything related to the booster, its sensors and switches is already covered. Throw a brake light switch at it? One other thought - the battery is the original, and although it seems to start the car fine, when I tested the voltage during the crank cycle (at the jump start posts in the engine compartment) it dropped to about 8 for a brief moment.

suginami · #12 01-28-2005, 05:57 PM

My mother has a '99 E430, and her owner's manual states that should the voltage drop below a certain level, the BAS / ESP lamps will illuminate.

Cycling the wheel from left to right helps the system "relearn" and the lights go off.

A new battery solved the problem.

vince · #13 01-28-2005, 11:02 PM

Paul - Thanks for the suggestion. The manual states that the BAS light will come on if the voltage drops below 10 volts, but that it should go out when the voltage is above that value again. I am seeing 12.2 volts with the key on/engine off, 14.0 with the engine running. The only time I see below 10 volts is momentarily during the cranking cycle.

The BAS & ESP malfunction indicators cleared without cycling the steering wheel, if that helps.

I will probably change out the battery anyway, but I am leaning towards the brake light switch first, if only to eliminate it as the actual problem. The problem is that I don't have anyone in this area that I really trust to fix the car. I used to trust the dealer, but they have thrown a lot of warranty parts at the car for various problems and still not fixed the problems. I usually give up and fix it myself. Plus they have trashed the interior and scratched the door jambs. Argggh.

zam2000 · #14 01-28-2005, 11:13 PM

Man, it's like reading script of what just happened to me two weeks ago. IDENTICAL SYMPTOMS !!!

Lucky me, I didn't listen to dealer diagnostic, but did a little research and tackle problem myself. Turn out it was the brake switch. Cost ? $14.

If either the BAS, or ASR light comes on, then it could be the brake pump or traction control modulation. But if both come on, it's the indication that the entire brake system jams. Now, notice that Mercedes build a backup pump into the brake system, so it's not possible that both pump failed at the same time. The only thing that indicate the brake system fail is the ...switch (spring broke, won't release the switch, which make the computer think the entire system has failed).

The brake switch locates on top of the brake pedal.

If you search around on Mercedes forums, you will find that this is a very common problem w/ Mercedes. That's why dealer stock plenty of them in stock.

Quote:

Originally Posted by vince

Thanks for the help. This is what the dealer says: "Brake booster pressure switch short test performed - code C1406. Electrical system check/det condition - found brake booster pressure switch intermittantly open." They replaced the booster and a couple of ancilliary parts (not the travel sensor, though). Which brings me back to my question - does this make sense? I am just trying to understand the interface between the ESP and BAS systems and make sure that whatever the problem, it gets fixed right before my extended warranty expires next month. Also, maybe this thread will benefit someone else down the road. I did flog the car after I picked it up and it seems OK. But, the problem was intermittant, so who knows. Incidently, I had checked tire pressures, they were spot on. I checked the battery voltage and it was fine. I did not check the brake lights.

vince · #15 01-31-2005, 09:49 AM

I pulled the brake switch last night. I tested both sets of contacts numerous times on the bench and then reinstalled the switch in the bracket and tested the switch using the brake pedal. So far I can't get either contact set to screw up. But, it is cheap so I'll get another.

I think I'll put a new battery in as a precaution - it is 6 1/2 years old and the BAS/ESP malfunction occurred (this time - the first occurrence the car was on the road) during that start cycle when I am seeing as little as 8 volts.