Well here's the latest... Took it to a shop and they tried to connect a scan tool ABS code reader to the OBD-II connector under the dash. The scan tool kept saying can not communicate.
He tried a different OBDII tool (much simpler) which did actually get information from the connector, but that unit wasnt capable of reading ABS codes.
I spoke with a MB tech, another euro car tech and a local oriely's part's guy... Got several different opinions and advice about this problem... Here's what I know now.
Start the car up, and NO lights are on at all. Which is a good thing.
If I drive the car UNDER 10 MPH, none of the lights ever come on. I've actually driven around the neighborhood under 10MPH and NONE of the ABS ETS BAS/ESP lights (or any lights for that matter) ever come on.
I was advised it could be a bad ABS sensor, thats why it only happens at >10MPH speeds. Talked with another parts guy who said those sensors RARELY go out (if ever) and he doubt's that's the problem, unless they've been damaged somehow. Apparently without actually removing each sensoring and looking at it, and cleaning it in the process - there's not way to verify if any of the sensors are actually bad, and at roughly $150 USD each, I'm not to anxious to just throw $600 at these lights without KNOWING that's the problem.
After driving the car and the lights come on (all 3 lights -- BAS/ESP, ETS, ABS) if I look under the hood, I can hear the abs pump working. (I don't know if thats good or bad, but I can hear it) and yes, after I turn off the car it does eventually stop running.
So from what I gather it could still be a number of things at this point.
1) Brake light switch - The previous owner claims to have replaced it, but you never know... I do know that the brake lights, gear shift, cruise control - all work correctly.. and usually when a brake light switch is bad one or more of those doesn't work.
2) ABS control module it self. Maybe that's why the OBDII scan tool couldn't communicate with it? It may be defective?
3) At least 1 or more damaged ABS sensors on one of the wheels. A quick visual look without removing them, they look ok - no torn or worn wires or anything.
4) Something wrong with the ABS pump control mechanism ( http://www.peachparts.com/shopforum/...d.php?t=163247 ) this seems to be a popular problem, and that thread has seen "action" for a while, unless I'm not understanding something there - because I can hear the ABS pump start and stop, I don't think its a bad solder joint on that pump since the pump seems to be behaving the way it should? But I DONT KNOW.
I'm really stumped. If anyone who has battled this problem can advise me - I would be grateful.
I had a problem similar to this, but mine went into limp mode. The can system actually turned off my abs, safety systems and airbags!!! Have your dealer check for the ground wire under the headlights. Mine was a damaged ground wire, it was replaced and all is good! It took them a month of trouble shooting and talking with techs in MB germany. 10-15mph is when the system does all the random checks, hence your codes coming up.
I to had this problem with an ml350 2004. after several right and left turns and no change. a tech removed and replaced the overhead console and no problems since. don't know the relationship between the console and the lights, but the problem has not recurred.
My car behaves in similar way, when I start the engine all 3 lights are off. When driving off maybe reaching 10-15 mph I can hear a short roaring sound and all 3 lights come on. This behavior isnīt consequent as sometimes the lights do not always light up, but lately they have?
My guess is that this is more likely to be a electrical malfunction rather then mechanical. Any suggestions ??
I would suggest swapping relays and see if that helps as this cost nothing.I doubt it is the solder joints as you have power to the motor good luck.I am not sure about whether are not the ABS motor should run constantly.It is still worth swapping relays.The relay#is K25. IF the ABS motor is loud it probably needs brushes and may be causing an intermittent problem.
I owned 2002 ML320 since new. Car now is having 105,000 Miles on it. Last December 2012, Merc. Dealer "Recall" to fix the Brake Light Switch/Stop Light Switch, then March 2013 those 3 lights "ABS, ETS and BAS/EPS" came on then off. Chat with Merc. Dealer about those light but when get there, then can't find the code. As advised by someone and on this web-site, today (09/14/2013) I went to get Brake Light Switch part from Merc. Dealer and put in by myself, when start up, no lights and yes, when drove slow around 10mpg those 3 lights came back on...very un-happy. Some mechanic suggested replace all abs sensors (omg...). Please advice if you can. Thanks. PS. Merc. Dealer advised bring car in for diag. but I didn't.
You had a new brake light switch put in last December, so that was still under warranty if it was faulty (which it wasn't).
BAS/ESP lights can be caused by any of several faults in that system, so you need the codes read in order to isolate the problem. For example, in the past owners have had faulty wheel speed sensors, damage to wiring, and bad ESP control module itself. Blind replacement of parts can only lead to further un-happiness and wallet drain.
If you are reluctant to have dealer diagnosis, shop around for a competent indie mechanic.
I also have the same problem (three yellow warning lights on) for a year. Today, I got the the test report (cost $200) from Mercedes dealer. The fault codes is "found high pressure and return valve in motor sticking requires new BAS/ESP pump assembly", ESP/BAS pump faulty & K25 ABS hydraulic relay faulty.
They confirmed that the problem was not caused by the replaced brake-light-switch in early 2012 recall.
Any good suggestion? MD quoted $4xxx for a new BAS/ESP pump. Thanks.
Maybe a little insight from my end - and a request for input from anyone who has a possible answer. My 2002 ML320 has done all the aforementioned. Repair was advised on everything from K25 relay, to rebuild ABS control module, to replace ABS Control Module, to replace ABS pump to replace brake switch. What I have done is have MB replace brake switch as a recall - issue not resolved. K25 relay has been changed - issue not resolved. Mechanic has cleared codes several times (had C1200; C1314; C1000 and C1120) all cleared but ABS/ESP light reinitiates right after. Only code now C1120 - yaw sensor (specifying N64 OR B24-15). Originally my brakes 'shuddered' when lights came on - now nothing. Just lights. Suggestions anyone?
I think there are a lot of factors contributing this problem - brake-light-switch, K25 relay, ABS control module, ABS pump, yaw sensor, ABS brake sensors, wiring, bad connector contacts, etc.
I'll go back to the Mercedes dealer for re-confirming all the error codes first. In my case, I don't think the problem is solely caused by the K25 relay. I swapped with other relay but the fault was not cleared. In the MD's report, it shows "Found high pressure and return valve in motor sticking". It should be the real fault issue if they could identify the "sticking" sound/noise coming from the motor!
By the way, I don't know whether MD's computer can identify faulty ABS brake sensors. If yes, this will narrow the possible faults.
Is your ABS function working? In my case, my ABS doesn't work. In wet road, I hardly pushed the brake and my car was sliding to stop.
MD's quotation is around $4200 for fixing this problem.
Again, thanks all of your information.
Last edited by derekML320; 09-21-2013 at 12:00 AM.
Reason: missin point
DrX - your reply is timely - albeit not conclusive. I am not a service technician and all I can really do is try to lascertain the reasons for my problem. As I said, and you quoted "I only have one code now. It is C1120" and according to MB that relates to the Yaw Rate Sensor. I went to MB yesterday and they said the only way to determine what caused the code to show up is "diagnosis". I suppose they feel that by chasing the REASON for the Yaw Rate Sensor to code will determine proper treatment. It MIGHT be the Yaw Rate Sensor but they kind of doubt it. Apparently anything from uneven wear on tires on same axle, to dirty wheel sensors, to rusty connections could be the problem. My concern is "why does the BAS/ESP system activate?" At 10-20 mph the fricking front brakes shudder and pull the vehicle to one side. That seems to be more of a ABS pump and/or control module to me - but the code say C1120 - Yaw Rate Sensor. I suppose the dealers have total control now cause it is really only them that can diagnosis. Sadly, costs to diagnosis, and then start replacing parts will probably amount to more than the bloody vehicle is worth now. Another Mercedes? NEVER.