Dreaded ABS BAS light

1534 Views 17 Replies 6 Participants Last post by MBGraham, Jul 16, 2015

cjesse44

Discussion Starter · Jul 9, 2015

2002 E320 Wagon 185,000 miles. I realize this topic has been discussed but I cannot find one post that talks to my issue as yet. I only have the lights but everything else works, cruise, brake lights, fuses good so no real symptoms. I know most solutions are the brake switch replacement but all the tests I have done from posts seem to have it not at fault. I am leaning towards abs pump or wheels sensor from all my reading but do not know how to diagnose short of stealer and Star scan.

Any works of wisdom lights on my dash make me crazy

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fosmith

· #2 · Jul 9, 2015

cjesse44 said:
2002 E320 Wagon 185,000 miles. I realize this topic has been discussed but I cannot find one post that talks to my issue as yet. I only have the lights but everything else works, cruise, brake lights, fuses good so no real symptoms. I know most solutions are the brake switch replacement but all the tests I have done from posts seem to have it not at fault. I am leaning towards abs pump or wheels sensor from all my reading but do not know how to diagnose short of stealer and Star scan.

Any works of wisdom lights on my dash make me crazy

Does the light come on when you tap the brake pedal? If so, it's probably the brake light switch. In any case, the switch is cheap (get it at the dealer) and by replacing it, you can check that off your troubleshooting list. Always good to eliminate the cheap and easy possibilities first before throwing expensive parts or STAR scans at the problem.

Fred

Check Codes

· #3 · Jul 9, 2015

cjesse44 said:
2002 E320 Wagon 185,000 miles. I realize this topic has been discussed but I cannot find one post that talks to my issue as yet. I only have the lights but everything else works, cruise, brake lights, fuses good so no real symptoms. I know most solutions are the brake switch replacement but all the tests I have done from posts seem to have it not at fault. I am leaning towards abs pump or wheels sensor from all my reading but do not know how to diagnose short of stealer and Star scan.

Any works of wisdom lights on my dash make me crazy

Look at the emphasized language in your post, because it's important.

If the BAS/ABS lights are on everything does NOT work, because those systems are disabled if the lights are on. So you're driving a car with no ABS, welcome to 1980.

That said, I agree with Fred. The best place to start is to replace the brake switch with a new part from the dealer (in person or online, mboemparts.com will have a great price and ship it free with code FB2015). While I also agree with you that this may not be the fix, it's always a suspect part for these malfunctions, it's a common failure point, it's inexpensive and easy to change, and you've eliminated it as a possible cause.

From there, though, I'd pay for diagnostics. Simply throwing parts at a complex, computer-linked system is going to be frustrating and expensive and time-consuming.

Good luck.

cjesse44

Discussion Starter · #4 · Jul 9, 2015

I have tried a few tests to eliminate the switch, only because the dealer is a hike away and I don't want to order aftermarket switch.

The ABS BAS lights are always on and never off regardless of brake peddle and I also disconnected battery to see if it would go away.

This why I suggest no symptoms for brake switch fault and thinking abs pump etc

I appreciate the help

cjesse44

Discussion Starter · #5 · Jul 9, 2015

Thank you Check Codes and Fosmith I will heed your advice and give the switch a whirl. I will report back with my results.

Again always appreciate the support, this forum has truly allowed me to afford to drive my favorite car to date

Kajtek1

· #6 · Jul 9, 2015

I like to start with easiest things and checking car voltage is such.
Checking for codes would be 2nd although I doubt standard scanner will read ABS codes.
Your choice is to get advanced scanner to pinpoint the problem, or start cleaning the sensors and rectangular (?) rings.

cjesse44

Discussion Starter · #7 · Jul 9, 2015

Good advice, voltage good, code reader I have not advanced enough (just ordered a new one) and I would like to know more about sensors and rectangular (?) rings. I assume you mean abs/speed sensor in wheel? If so I will look on line how to access and clean. Are the rings the part that holds them in? I will research and Thank you

Kajtek1

· #8 · Jul 9, 2015

It is RELUCTOR ring. Sorry, I could never memorize the name.
Lot of images on youtube but could not find one for W210.
When you have time, taking wheels off and cleaning/inspecting everything will be time well spend.
ABS sensors seldom show problem outside so you can't tell them without advanced scanner, but corroded rings are often reported by UK members.

MBGraham

· #9 · Jul 9, 2015

If you think it could be ABS pump, there is something you might try.

What goes wrong with the pump, is that the brushes in the pump motor wear down and no longer make proper contact.

Each time you start the car, the computer checks to see if the ABS system is working. To do this it tries to run the pump. If pump doesn't run. you get the ABS and other lights.

I found that I could get the pump to run by tapping it with a rubber mallet or something like that. Best to do it while someone turns key on and keep doing it for a minute or two. You may hear the pump run. In fact you should listen to see if pump runs first. If it does, problem is likely elsewhere.

Regarding code readers, I don't think any OBD2 meters will read the relevant codes. You need to have a Star type system. Even then, the codes will be cryptic, because there are a number of inter-related systems which affect each other. However, if it is a wheel sensor, I think you get a specific code.

When I had similar lights, I did following:
- changed brake light switch (made no difference)
- Had codes read by Indy. He had no clue, but I had him give me the codes.
- With codes, searched internet including here!
- Finally found some stuff on ABS pump brushes.
- Bought used pump and installed.

No lights since! And ABS does work.

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cjesse44

Discussion Starter · #10 · Jul 9, 2015

Great idea and I have held a screwdriver to the pump but sounds faint if non existent. Should it be loud and also the sound gets muffled when the purge valve start ticking. Cant tell if pump is going? Any advice?

MBGraham

· #11 · Jul 10, 2015

2

cjesse44 said:
Great idea and I have held a screwdriver to the pump but sounds faint if non existent. Should it be loud and also the sound gets muffled when the purge valve start ticking. Cant tell if pump is going? Any advice?

I would have to check on our car. I do recall hearing the pump run.

You could pull the plug off the ABS pump. Then apply 12V to the pump. Then it "should" run. If it does (but not when you turn key on), then move back in electrical system to say pump relay and fuse. I recall that finding those was another challenge

There are two wires to the pump that supply 12V. Red and Brown. You can see them in pics below. The sockets are the ones between 12& 13 (brown, neg) and between 13&14(red, pos). Just pull the plug, then apply 12V briefly to the corresponding pins on the pump observing the polarity. You should hear pump run. If it doesn't give it a bump with mallet or whatever and try again.

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cjesse44

Discussion Starter · #12 · Jul 10, 2015

Wow fantastic MBGraham that is super helpful and Thank you for the pictures. I understand completely and will test tomorrow after work. You will find this amusing, Kingston is my home town and my parents recently moved to Gananaque out of the city. I live in London ON now. Small world and Thank you. Smart people come from that area ; )

MBGraham

· #13 · Jul 10, 2015

cjesse44 said:
Wow fantastic MBGraham that is super helpful and Thank you for the pictures. I understand completely and will test tomorrow after work. You will find this amusing, Kingston is my home town and my parents recently moved to Gananaque out of the city. I live in London ON now. Small world and Thank you. Smart people come from that area ; )

Definitely small world!

One caution. My w210 is a 98 model. The abs pump i have was, i believe only used on 98 & 99. Your connector may be different. But hopefully it will have similar power wires to allow you do the test.

Good luck!

kstreufert

· #14 · Jul 10, 2015 (Edited)

If you disconnect and reconnect the battery the BAS and ABS lights will come on once the car is started. You will have to turn your wheels full left to full right a couple of times to get the system to reset and the lights to go out. Before I went any further I would follow the good advice you received earlier and replace the brake switch (a cheap easy fix and the most common fault.) In addition make sure your battery is in good condition. A weak battery can also cause this issue.

cjesse44

Discussion Starter · #15 · Jul 11, 2015

Yes Thnakyou I did learn about the wheel turning by accident but this time no luck. I guess as all of the responses have indicated I will do the brake switch. It's worth a go as it's the cheapest fix and will be preventative maitence.

cjesse44

Discussion Starter · #16 · Jul 16, 2015

Alright all the suggestions have been completed, new brake switch, tested abs pump, turned steering wheel disconnected battery etc. I even was replacing front shocks and cleaned the 2 front speed/ abs wheel sensors. All with no luck &#55357;&#56862;. So can you please help direct me to the next line of tests, I did read if battery is on way out it may be the issue with abs lights. I assume just a volt meter on pos and neg and see voltage?

I await some worldly advice, I have my business card taped over the lights&#55357;&#56865;

cjesse44

Discussion Starter · #17 · Jul 16, 2015

I wanted to eliminate the battery as a suspect here so I used

methodology and checked via climate control. Off 12.0 v on with all lights 13.5 so it appears to be good. Yes? I don't have a dealership close and most indies cant read abs codes or can they?

Help on next step please

MBGraham

· #18 · Jul 16, 2015

cjesse44 said:
Alright all the suggestions have been completed, new brake switch, tested abs pump, turned steering wheel disconnected battery etc. I even was replacing front shocks and cleaned the 2 front speed/ abs wheel sensors. All with no luck ��. So can you please help direct me to the next line of tests, I did read if battery is on way out it may be the issue with abs lights. I assume just a volt meter on pos and neg and see voltage?

I await some worldly advice, I have my business card taped over the lights��

You can display the battery voltage on the climate control. During starting, it will drop quite low. Perhaps below 10V. I copied this from another BW post (should also be in stickies):

Ignition on AC off, press and hold "rest" until display changes then press left "auto" several times to get to #24 on left of screen. Voltage is displayed on right, then start up and see what it changes to.

You should initially see battery standing voltage (say 11.7V), then a drop as starter pulls voltage down, then the alternator voltage (about 13.3V). To check battery, you should do a load test. I have a cheap tester from Princess Auto, but perhaps battery shop would do a test for you? Some how, if car starts well, I doubt battery will be the problem.

Regarding the abs pump motor. Did you apply 12v from an external source several times to see if motor ran each time? (with everything else turned off).

But really, at this stage you need to get the codes read.

I was away from home when I had similar need. Had to pay a garage US$300. A local dealer or independent might run the diagnostics for you for less. Our local dealer, who I know well, ran them for me on another car we owned for less than an hour's labour charge and provided me with the printout. Another option is to find someone in your area who has Carsoft or later better diagnostic scanner/software.

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