Another ****** BAS\ASR light....

[andy_burnton]

Hi Guys,

My W reg C180 has, it seems, gotten to that age where things start going wrong.

The latest one is the BAS\ASR light coming on just after starting.

I searched the forum and followed the consesus here and replaced the brake switch. Dam! it's still doing it.

Tried an experiment:

Started car in the driveway (light off) and put my foot on the brake (light still off), when I took my foot off the brake the light came on. Did this twice.

Anybody point me in the right direction ?

Thanks in advance.

Andy

 

[television]

Is the fault still there Andy after a warm start and the car has been driven,, say the car has been driven and re started, is the fault there or only after a cold start, by W I take it its a 202

 

[mercman123]

ASR/BAS lights

Hi Andy

Just read your post and thought i would let you know that i had the same problem with my C250TD. Dont know if they are a similar model but mine was the front offside speed sensor. It was very easy to fit and cost me £45 from the merc dealer. Non of the independent parts dealers had one. I first took the car to a couple of garages who tried telling me that the rear drive shaft was probably broke and quoted me £600 to replace !! and a few other ideas that were banted about. I ended up going to a very good auto electrician who diagnosed the fault with the computer and charged me £30. I would take it to a similar place if i were you and then you know that your not stabbing in the dark...................................

 

[dragon]

Hi Andy

Just read your post and thought i would let you know that i had the same problem with my C250TD. Dont know if they are a similar model but mine was the front offside speed sensor. It was very easy to fit and cost me £45 from the merc dealer. Non of the independent parts dealers had one. I first took the car to a couple of garages who tried telling me that the rear drive shaft was probably broke and quoted me £600 to replace !! and a few other ideas that were banted about. I ended up going to a very good auto electrician who diagnosed the fault with the computer and charged me £30. I would take it to a similar place if i were you and then you know that your not stabbing in the dark...................................

Did you take a note of the software running in that computer?

 

[kebo57]

Hi I have had this ASR/BAS lights coming on narrowed it down to the relay
I swapped the ASR/BAS relay over with one that was similar in the fuse box
I cant say that will fix your problem but it wont cost any thing to try

Kevin

 

[andy_burnton]

Thanks

Hi Guys,

Thanks for the replies.

Malcolm: Yes, within few minutes of driving it comes back on again. It is a 202.

Kevin: Thanks for that, I'll give it a try.

Cheers,

Andy

 

[dragon]

Use diagnostic tool to read the error codes. If you don't have one then pay someone to do it.

 

[andy_burnton]

Update

Thanks Dragon, I have purchased one on eBay. Will post solution for others when I find it.

I did swap the relays: same problem.

Also checked the battery voltage: 12.7 without engine running and 13.7 when running. Seems OK to me.

Cheers,

Andy

 

[dragon]

Mine comes on eveytimes I put my car off the road and disconnect the battery. The manual said, turn the steering extreme left and right, the light goes off.

 

[mercman123]

software

Dragon

No i didnt take note of the software unfortunately. I do know though that the auto electrician used 2 different machines to diagnose the fault because one of them brought up the fault and the other one was saying that no fault existed. Strange. ?????????

 

[andy_burnton]

More updates

Noticed an interesting thing this morning. It was a cold morning (+3). When I started car and pulled away, no warning light on when I braked. I tried stomping on the brake and accelerating hard, still no light.

When engine had warmed up I touched the brakes and light came on. Came on first touch of the brakes from then on.

Strange or what ?

Can't wait to see what the error code is for this....

Andy

 

[television]

This will be a front wheel sensor I think

 

[kebo57]

I have purchased one on eBay "diagnostic tool"

Andy

Hi Andy I want one "diagnostic tool" which would be the best one to buy
Any help would be greatly appreciated

Kevin

 

[andy_burnton]

Diagnostic tester

Hi Kevin,

Haven't got mine yet, but I'll post when I've used it and let you know how I got on. I did find out that I needed an adapter cable as my car has the 38 pin socket.

Cheers,

Andy

 

[dragon]

Noticed an interesting thing this morning. It was a cold morning (+3). When I started car and pulled away, no warning light on when I braked. I tried stomping on the brake and accelerating hard, still no light.

When engine had warmed up I touched the brakes and light came on. Came on first touch of the brakes from then on.

Strange or what ?

Can't wait to see what the error code is for this....

Andy

It trying to tell you something, ignore it at your peril.

Use diagnostic tool to find out, if you don't have, ask someone to do it for you.

 

[andy_burnton]

Update

Dragon,

I have purchased a diagnostic tester and am waiting for it to arrive.

I only included the other stuff in case somebody did a search for that type of fault in the future.

Cheers,

Andy

 

[andy_burnton]

More info

This gets stranger by the day.

I tried using my cruise control this morning while the bas\asr light was on and it WORKED.

All the posts I've read regarding this problem say that cruise control doesn't work in this situation but speed limiter will. Both work on mine.

Wierd.......

Should have code reader by the weekend when I hope to get a solution.

Cheers,

Andy

 

[andy_burnton]

Code Reader

Got the code reader and the 38 pin adapter at the weekend. Plugged it in and hit the button to read the codes. Displayed - - - - (no errors). This is while the BAS\ASR light is still on.

I tried clearing the error log as described in the handbook of the reader and tried again. Same thing.

The code reader is the correct one ( for C class Mercedes ) and seems to be working as described in the booklet, it just doesn't find any error codes.

Why would that be when there is obviously a fault ?

Other than the light being on I can't see anything affected by this problem. As I said before, cruise control still works and the car drives fine.

Help !! (lising hair by the minute now.....)

Andy

 

[RonH]

Might be this.

Hi Andy,
had similar experience with my 2.3 16v. ie. BAS/ ASR coming on, staying on, sometimes staying off for short time and then coming on again.Turned out to be a bad earth connection on the inner body wall near to the bottom of the battery tray. I believe the BAS/ ASR relays are earthed at this point. Mine came to light after changing the battery....inadvertantly disturbed what turned out to be a seriously rusted bolt and thread.
Have a look ....might be same problem!.
Ron H.

 

[television]

If the ABS pump failed, then the speed signal would still be there, then if the fault was the ASR would the ABS lamp come on, do they share the same lens in the cluster,, does the brake pedal pulse when the wheels are locked