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ABS BAS ESP Lights Issue Check-list

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58K views 46 replies 16 participants last post by  OKB3436  
T
#1 ·
Hi,
I have read so many forums regarding this inherited issue of w210 (ABS BAS ESP Lights pop-up). To help precisely and easy to follow steps for any current or future victim, I shall be really grateful if some of us can make a final check-list regarding this issue, starting from:
1- Replacing the Brake Switch
2- Re-flowing or finally replacing K-40 Relay
3- Confirming correct behavior of all 3 Brake lights
4-
5-
6-
7-
8-
9-
10-


Thanks!
 
M
#2 ·
Hello:)

Do you have a problem, and if so, describe your problem.

The first step is to read your fault memory in the ABS/BAS/ESP modules via a suitable scanner that can read fault codes from individual modules, and find out what the problems are. The codes are classified as "B" and "C" codes, like B1040 (B1xxx), or C1000 (C1xxx).

Based on that you determine your course of action.

The fault indicators on the instrument panel, come at various stages of driving, and for various reasons, and depends on the model year and model of the MB. So a generalized list will not help that much.
 
#3 ·
mrboca is correct.

I have posted about this before, but in my case it was the ABS pump motor. Codes were kind of cryptic, but did lead me to check the pump.

When you start car, system checks to see if it is working. If it does not spin, you get the error. Not hard to check. Use a stethoscope or hold hand on ABS pump motor while someone starts the engine. Determine if the motor runs or not. For us it was intermittent at beginning, later at every cold start.

Problem is just bad brushes, but on our model the motor is sealed. So you get to change a $2000 items instead of a $5.00 set of brushes :( (Luckily found a good used unit)
 
T
#4 ·
Hi,
Thanks for your inputs. We are talking here about generalized kind of few major possible issues, when ABS|BAS|ESP lights suddenly appear in W210 from 1998-2002 (or any other related models)

Most Possible Issues:
1- ABS|BAS|ESP lights suddenly appear on dash, while driving
a) Lights go OFF, when doing lock to lock steering rotation (full left - full right - center)
b) Or, lights remain ON, when doing lock to lock steering rotation (full left - full right - center)
2- Lights, instantly appear on pressing brake paddle.
3-
4-
5-


Let me re-arrange the list based on your expert inputs:

1- Get your vehicle scanned (if possible), proceed accordingly.
2- Replacing the Brake Switch
3- Confirming correct working of ABS pump's motor (using a stethoscope or hold hand on ABS pump's motor while someone starts the engine)
4- Re-flowing or finally replacing K-40 Relay
5- Confirming correct behavior of all 3 Brake lights
6-
7-
8-
9-
10-



Thanks!
 
M
#5 ·
could be many things..

As has been said this one requires a scan if the brake light switch fix fails.

There are many sensors that are checked and if any fail it shuts down.
In my case there were 2 sensors on the brake booster that caused the error.

Hope this helps.

B
 
S
#6 ·
Have no brake lights, BAS/ESP & ABS warning light off at vehicle start. From above post: 2- Lights, instantly appear on pressing brake pedal. Did the wheel centering, rt-lt-rt-lt, etc. Have replaced brake switch, worked for a couple of weeks. Shut off car, lights go out on restart but immediately return once brake pedal depressed. Was going to check the wheel speed sensors with Voltmeter, but it appears the plugs to check at are somewhere inside my trunk , not accessible from under car. Lots of bolts to remove the trunk cover area. Any other thoughts on troubleshooting, my VIDENT scanner isn't showing any faults..
 
M
#7 ·
Welcome :)

Please specify the model and model year for your car in your profile.

If you press the brake pedal and there is no brake light, and you changed the brake light switch, I would check the fuse, and the fuse holder which is on the driver's dash side under a lid. I believe it is fuse 2. It should be in the the list provided inside the lid.

Sometimes a loose fuse holder can cause intermittent problems.

It appears that your scanner can connect to the 38 pin connector and check codes on the modules like the ECU, ETC, TCM, etc, etc. Scan for all codes from all modules.
 
S
#8 ·
I've done the switch and it fixed it for a couple of weeks. Swapped the fuses, didn't go away. That the lights reset when the car is restarted (not depressed pedal yet) seems like the fuse or something intermittent but am checking the rear wheel sensors as soon as my son gets out of the shower. Why did the put the disconnects behind the trunk shroud to the back seat. Not smart, but that's why the troubleshooting and replacement costs $500+. Thanks for your response, I'm going to check tonight or tomorrow...
 
M
#10 ·
But, why would the speed sensors cause a fault if the car is not moving ? My understanding is, you turn the ignition on and there is no fault, no lights, and you press the brake pedal and warning lights come up, even when the car is not moving ?

The VSS (vehicle speed sensors) generate signals when the car is moving. If there is a wiring issue, and this is detected by the Traction module, the fault would come up even before you press the brake pedal.

Confirm that the brake lights do NOT turn on, after you pres the brake pedal, and the ABS/BAS/ESP lights turn on.
 
S
#12 ·
The troubleshooting sequence I've seen elsewhere points at them. I thought they were more accessible. So I'll reiterate my problem:
1) Car starts fine, new BOSCH Gel battery back in July 2018 (26.4 - 27.5 volts with car not running--~26 with car running),
2) brake switch replaced (before battery), both with battery connected & disconnected. Worked for about three weeks , then no brake lights. No dash lights (car running) until brake pedal depressed,
3) Turn car off, @ restart no ABS, BAS/SAP light until brake pedal depressed,
4) Car runs otherwise fine, no limp mode, acceleration is fantastic,
5) My Vident iLink400 shows no codes for ABS, BAS/SAP, steering sensor, MAF sensor, etc...
 
M
#15 ·
1) 26V ? Are you sure you measured it right ? Car batteries are rated at 12V (even though the fully charged battery is about 12.8V).

2) If the brake switch is replaced and no problems for 3 weeks, then no brake lights, you have a disconnect somewhere. Bad brake switch, bad connection to the switch, bad fuseholder / headlight control module, bad wiring, etc. The speed sensors only come into play if the lights come up while you are moving. Then again you will likely get a CEL from the transmission and the car may get into limp mode (not always though). If the lights pop up when the car is not moving, it is something else.

5) The Vident Ilink400 only accesses the OBD2 port (unlike Ismart which has an adapter). For 2000 W210, you will not get ABS/BAS/ESP codes from the OBD2 port. For W208, I am not sure. If the car has a 38 pin diagnostic connector, it is certain that these codes will not be available from the OBD2 port.
 
S
#16 ·
1) That voltage is was incorrect @ 26.4, IS: 11.95 static & 12.68 running. Have .2V on the A/C 200V scale turning the rear wheels either direction. Fronts the same, wheel sensors seem okay. Have 9.1V (200V scale) coming out of the trunk plug that would connect to the wheel sensor, not sure what that should be (this is with the ignition on, pos. 2, engine not running).
2) Start car, all dash warning lights off until I step on the brake. Put original brake switch back in, same result, ABS, ESP/BAS lights illuminate.
3) Replaced brake switch with both the battery disconnected and connect, ignition off.
4) Have reset the plunger length on brake switch,
5) Have swapped fuses (#2), but haven't pulled the fuse block to see about connections as someone else suggested (re-solder of connections?)
What else would trigger an illumination of these lights? Using the 38-pin chassis interface, get no trouble codes on my Vident Ilink400 scanner. Do not want to go to the dealer, but for the $$$$, can't use the car otherwise as no brake lights with these dash lights on...
 
M
#17 ·
One more thing that can cause the brake light problem is the K55 relay which is installed in series with the brake light switch in series for cars with the ESP. It is to prevent the brake lights to be turned on when the ESP is activated, and you press the brake pedal.

The location of the K55 relay is likely in the same place as a in W210 which is on the driver's side fuse and relay module (the black relay).

You could whack the relay when someone presses the brake switch, and see if the lights come on. Or you could pull it out and and put a jumper between 30 and 87a contacts temporarily and press the brake switch with the ignition switch in position 2, and check the brake lights. I believe the relay has single pole double throw type so there would be 87 and 87a contacts. 30 and 87a must be normally closed, and 30 and 87 is normally open. When ESP is active the NC contact opens to cut the brake light circuit. If the relay is bad, then the NC contact may be open.

Also double check that the fuse #2 is not blown.
 

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S
#20 ·
1) That voltage is was incorrect @ 26.4, IS: 11.95 static & 12.68 running. On voltmeter, have .2V on the A/C >200V scale turning the rear wheels either direction. Fronts the same, wheel sensors seem okay. Have 9.1V (>200V scale) coming out of the trunk plug that would connect to the wheel sensor, not sure what that should be (this is with the ignition on, pos. 2, engine not running).
2) Start car, all dash warning lights off until I step on the brake. Put original brake switch back in, same result, ABS, ESP/BAS lights illuminate.
3) Replaced brake switch with both the battery disconnected and connect, ignition off.
4) Have reset the plunger length on brake switch,
5) Have swapped fuses (#2), but haven't pulled the fuse block to see about connections as someone else suggested (re-solder of connections?)
What else would trigger an illumination of these lights? Using the 38-pin chassis interface, get no trouble codes on my Vident Ilink400 scanner. Do not want to go to the dealer, but for the $$$$, can't use the car otherwise as no brake lights with these dash lights on...
 
M
#21 ·
Using the 38-pin chassis interface, get no trouble codes on my Vident Ilink400 scanner.
Click to expand...
No need to put the same response again. I do not think your scanner is scanning the modules (at least not the traction module). Otherwise you would have seen CXXXX type fault codes from the traction system. So unless you have a proper scanner you will not be able to access the module data.


Have 9.1V (>200V scale) coming out of the trunk plug that would connect to the wheel sensor, not sure what that should be
Click to expand...
. If in the same location, this is most likely for the brake wear sensor (which is really a switch).

Your main problem is the brake lights not coming on. I believe the ESP/BAS/ABS lights coming on is the consequence, as the traction module monitors the switch pair inside the brake light switch (there are two switches, one is normally open, and the other is normally closed). When you press the brake pedal, NO switch (THE BRAKE LIGHT SWITCH) becomes closed. and the NC switch (THE TRACTION SWITCH) opens. If this does not happen, you will get an the ABS/ESP/BAS lights to go on.. If the brake light switch gets power from the Illumination Control Module (ICM) (through fuse 2), and it does close when you press the plungers, the only thing left is the return wiring (back to the ICM), and the K55 relay contacts in series with this wiring.
 
S
#22 ·
1) Relays labelled after fuse bank: A (thin/narrow black), B (green), C (5-prong yellow), D (5-prong yellow), E (5-prong yellow), F (4-prong black) & G (no relay). These all seem to be stock Mercedes relays. My replacement ones (#4 below) are all black.
2) Is K55 four-prongs? Removed this 4-prong relay from F slot (Slot C, D & E have 5-prong relays, 87a in middle), jumpered 30 to 87 as lugs are 30, 85, 86 & 87, get LED lit no ignition on & no brake lights (BL's).
3) Removed relay from E slot (forward of fuse area and in-line with F), jumpered 30 to 87a, no light @ LED (key on or off), no BL's. Jumpered 30 to 87, led lights up when key only, no BL's.
4) Replaced all relays one at a time and all together using HELLA relays, still no BL's, ABS, BAS/ESP ulluminates after brake pedal actuation.
5) #2 Fuse is good but swapped with one from trunk fuse panel, is not loose in slot, still no BL's.
 
M
#25 ·
The K55 is a 5 prong relay, at least that is what the diagram shows.

Have a look at the diagram attached.

1)Locate N7-1 (in U153 (which is for W208, your car)

2) Start from pin designated with 15 (that is circuit 15, where the power comes from when you turn the key to position 2.

3) Follow it through the K55 contact to the S9/1 contact (closed when brake pedal is pressed), then back to N7-1.

This is your brake light activation circuit.

You can do the following:


1) Remove brake light switch
2) Turn the key to the ignition switch position 2.
3) Measure the voltage between the terminal where the black/white wire comes in, and chassis ground (metalwork) You should read 12V (battery voltage). If you do not, either the ICM (which is the other name for the headlight control module) is not supplying the voltage, or the K55 relay is open, or some wiring issue (check the wires for pinches near the brake pedal).

If you have 12V at the black/white wire, then if the brake switch (s9/1) is fine, you have a problem with the return wiring (shown with black color) going through the X47 connector block.

Note: The fuse panel at the side of the dash is integrated with the ICM.
 

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#28 ·
INTERESTING THREAD.... MY BAS/ESP ABS LIGHTS ON WITH CAR START, BRAKE LIGHTS ONLY WORKING ON THE MIDDLE LIGHT IN THE REAR WINDSCREEN.....

DONE:
FOUND A LOOSE CONNECTION IN THE TAIL LIGHT ASSEMBLY....WHICH I FIXED..... BRAKE LIGHTS NOW WORKING....
TESTED THE WHEEL SPEED SENSORS ALL GAVE A READING OF 1.79-1.86 OHMS....


A LITTLE BACKGROUND INFO: MY TRANSMISSION GOES INTO LIMP MODE WHILE DRIVING, WHICH I RESOLVE BY RESTARTING.... THIS LIMP MODE OFTEN OCCURS WHEN I NEED TO SLOW DOWN ON BAD ROAD PORTIONS....AND IF I MAKE A SUDDEN U-TURN MY GEAR SHIFTS VIOLENTLY LIKE A CAR WITH FAULTY WHEEL SPEED SENSORS.... I AM ON THE VERGE OF REPLACING THE TRANSMISSION, BUT I WANT TO FIX THESE ABS/BAS/ESP ISSUES FIRST....


THANKS MRBOCA FOR THE JOURNEY SO FAR
 
S
#29 ·
Final Brake light fix

So when I first started having this trouble (no brake lights, ABS ESP trouble lights on dash) checked the brake light switch plug for power and the fuse and had power. Replaced fuses, BL switch and ESP module ($40 used, now have an extra). Turns out after going to third mechanic and this time paying $150 for full diagnostic, was bad connection in headlight switch/fuse panel assembly. Campbell Mercedes Repair in San Jose, Ca finally found the trouble, using the very expensive Mercedes diagnostic laptop. Should've gone there first as I purchased $100+ bucks worth of parts that are now spares and countless troubleshooting hours on an intermittent trouble. Know a lot more about the car now though. Thank you to all those who were part of that path to this solution...
 
M
#30 ·
Hi all.

I discovered that my brake light switch was faulty after assistance from your posts. Instead of replacing it I cycled the switch plunger rapidly about 20 times. I repeated that after spraying WD40 (actually Q20 spray being in South Africa) into the switch. That did the job and the switch has functioned perfectly ever since. I waited 2 months before I decided to post this so it wasn't just a momentary fix.

Cheers
Mark
 
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