Mercedes-Benz Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
65 Posts
Discussion Starter #1
I'm having a problem with the ABS/ASR lights staying on when I first start my 94 320SL. Mechanic said that it was a problem with the speed sensors. Replace both front sensors. Lights still come on. When the car warms up however and I turn the car off and re-start it, they stay off. They never go off by them selves after the car reaches operating temperature. I'm told that the electronics on the 129 are sensative to the cold. Has anyone else had this problem? Could it be because of the cold in NJ or a wiring harness issue or other. The SRS light also stays on for about 2-3 minutes but does go out.
Any thoughs from others is appreciated.
 

·
Registered
Joined
·
104 Posts
If the batery has been disconnected or run flat these two lights stay on, even when there's no problem in the system. A merc dealer or speciallist should be able to reset them. I had the same problem when I bought a 1991 R129 a couple of weeks ago. It had been left standing over the Christmas and new year break and the TOAD had flattened the battery. It was taken to a merc specialist who reset the system. Batteries are definately sensitive to cold.

I gather there are sometimes problems with the wiring loom on the 93s and 94s chafing and causing wear that results in shorts, although I've not heard any stories about the loom being sensitive to cold.

Hope this helps.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #4
Code Reading

Thanks Bob for the offer. I've made a code reader based on the information I've
gleened from the forum. My car only has the 16 pin socket. Both light come on at the same time which leads me to believe it might be a short or something. As I wrote, when the car is cold the lights come on until it warms up. Then, if I turn it off and restart, they go off. They never go off unless I restart. What codes and what socket could I test to see if there is a trouble fault? Also, in using the LED do you hold the button and keep the light on 2-4 seconds or release it to get the fault to light.
I have disconnected the battery to try to clear the fault. Should I try that again?
Thanks for your help.
Roy
 

·
Outstanding Contributor
Joined
·
4,109 Posts
royvan said:
Also, in using the LED do you hold the button and keep the light on 2-4 seconds or release it to get the fault to light.
Yes.

royvan said:
I have disconnected the battery to try to clear the fault. Should I try that again?
I don't believe this can help. But it can't hurt.

Roy, if your car has a 16-socket connector I don't believe you can read codes for the ASR/ABS. But the info I has shows that you should have the round 31-socket connector...

If you send me an email, I can reply with a very basic listing of the codes. But I recommend that you purchase the R129 Tech DVD from MBUSA for about $75 (1-800-FOR-MERC). If that's more than you want to spend, I suggest the Mercedes WIS software that you can buy on eBay for about $15 shipped.
 

·
Registered
Joined
·
77 Posts
i have the same problem... some times i get abs /asr lights on and i need to restart the car to reset it.. it doesn't clear it self ... i think the problem related to the battery voltage and connection..if you got low voltage u get the lights on and need to restart the car to reset it. check the positive plug ont the battery there is a red wire ,,make sure it is connected to the plug and free of carbon..
 

·
Registered
Joined
·
153 Posts
Brake switch

Could be a faulty brake switch, in the drivers area just above the brake pedal,
I replaced mine and have never had a problem since with the abs/asr light staying on, it is a bitch to get at though....
 

·
Registered
Joined
·
65 Posts
Discussion Starter #8
Abs/asr

I've read about the brake switch but wondered why the light still comes on without even depressing the brake. I'll try a voltage check and cleaning the contacts. Also, Bob's suggestion about the DVD is good. My car does not have the 32 pin socket. It's a 1994 320 SL and only have a 16 pin socket. Having the sockets locations and fault codes will help. Hope it warms up on NJ soon so I can get this baby straightened out.
 

·
Registered
Joined
·
65 Posts
Discussion Starter #9
Asr/abs

Bob,
I tried to send you a personal e-mail but, your message box is full. I would appreciate getting the codes. I'm not sure that I'm using the reader correctly. When I press the button on it I get a light on all sockets. Do you have to release the button after you get the light for the code to appear?
Seems funny also that the brake light would be the problem since the light comes on even though I don't depress the brake peddle.
 

·
Registered
Joined
·
105 Posts
i have this problem too, i test pin #6 on the connector and the results was 4-15-27 blinks error code: what does it mean?
 

·
Outstanding Contributor
Joined
·
4,109 Posts
Codes 4 and 27 indicate a problem with the left-rear wheel speed sensor, and code 15 indicates your ABS/ASR control module needs to be replaced.
 

·
Registered
Joined
·
105 Posts
sometimes the abs asr light on the console stays on especially when the engine is cold, when i restart usually it's off when thr engine is warm;i washed the engine last month, should it be the cause of the fault of the abs/asr module? how much does it cost? i erased all error codes yesterdaw and today in the morning the abs asr lights stayed on again , i retest pin #6 with the code reader and only error 4 this time??????????thanks!
 

·
Outstanding Contributor
Joined
·
4,109 Posts
I don't know the cost of a replacement module. I'd take a look at the wheel speed sensor at the left-rear wheel and look for damage to the wiring. If you have the WIS you will find there are electrical tests for the sensor.
 

·
Registered
Joined
·
14 Posts
Looking for advice regarding ABS ASR lights that came on with my '95 SL500. I've read through all the threads on this topic I believe and still struggling to fix.

Symptoms: both lights on, speedometer bouncy. Otherwise car performance is fine. With 32 pin diagnostic connector, pin 6 has 3 flashes. (My diagnostic book is giving me conflicting info: one page says "left VSS sensor open circuit" and another page says "right VSS sensor open circuit" for this fault depending on model year but both list 1995).

Attempted fixes:
Battery voltage: 12.5V car off, 14.1V car on
Cleaned drivers side front speed sensor. Even swapped it with one from my SL320.
Cleaned passenger side front speed sensor (this one looked different - the surface was flat/didn't have the metal piece protruding out)
Cleaned drivers side rear speed sensor.
Replaced engine wiring harness (had this anyway and had been putting off the task).
Checked the 10 amp fuses in control module compartment

My next steps (in this order):
1) swap passenger side speed sensor with one from my SL320.
2) swap control modules with ones from my SL320

Am I missing something or any other suggestions? Fortunately I have the ability to "swap parts" before buying anything. Thank you for your help.
 

·
Registered
Joined
·
14 Posts
Now that my son is back from college I am able to get back to the problem. With BobTerry's link to the manual, I was able to better diagnose the problem. Chapter 9.1, test 13.1 identified the problem. Across controller pins 10 and 30 I'm supposed to have 0.8-2.3 KOhms. I had over 200K Ohms. Then to identify where the problem was, I measured from the speed sensor plug on driver's front wheel to the plug between the fusebox and brake fluid reservoir. Wire 1 had no resistance, wire 2 had over 200K. Bingo! (I even compared to my SL320 to confirm the resistance should be almost zero with both wires).

Very odd failure given the wire has no cuts or abrasions. Anyway, ordered a used one on ebay for $30 but now must wait a week for it to arrive. I've attached a pic of the wire/cable from the left front wheel up to the fusebox area. It is for both the speed sensor and brake pad wear sensors.

BTW, not that difficult to remove the wire if you ever need to. Take the fusebox end and feed it through the wheel well.
 

Attachments

1 - 17 of 17 Posts
About this Discussion
16 Replies
7 Participants
Brett Humphrys
Mercedes-Benz Forum
BenzWorld.org forum is one of the largest Mercedes-Benz owner websites offering the most comprehensive collection of Mercedes-Benz information anywhere in the world. The site includes MB Forums, News, Galleries, Publications, Classifieds, Events and much more!
Full Forum Listing
Top