asc and abs lights on.Help needed please.

[Antm72]

A code reader should extinguish them i have an intermittant light but normally power cycling the car and driving it a little always puts it out.
A lot of people seem to experience alsorts of odd errors after a flat battery.
The last owner of mine flattened it and on powering up it killed the OBC.
The abs pumps seem to be a common fail on a zed according to the net dry joints in the circuits on the module a common cause

 

[t-tony]

Low, or maybe more correctly, lowered battery voltage can cause a multitude of these type of issues. If the car is road legal, ie. not sorned I would do as Dave suggested and give it a good run. Just be aware that although the brakes will work fine the ABS won't if the light is on.

Tony.

 

[Mint]

...If the car is road legal, ie. not sorned I would do as Dave suggested and give it a good run. Just be aware that although the brakes will work fine the ABS won't if the light is on.
Tony.

You can have fun driving whilst diagnosing the problem....win, win

 

[zedonist]

Two common problems here, one is easy, its a wheel sensor, change them, code reader will tell you which one. The other is the ABS/ASC control unit, it gets dry joints over time and needs repairing cost about £150.

The resetting of the lights should not need a code reader once the repairs are done, as this is one set of sensors on the car that goes through a diagnostic every time you start the car, if it finds no faults after a short drive (200 yards) the lights will extinguish.

Other things that can trip the abs / asc lights:

Uneven road surface
Dirty sensors
Incorrect toe on the front wheels
Wheel spinning and donuts
Incorrect tyre pressures or uneven across an axle
Worn suspension components
Coil pack or ignition system breaking down (The ASC works by cutting the spark to the engine as well as the applying brakes)

A combination of all the above.

 

[Lexybhoy]

Hi Lexybhoy.Well the short answer is I don't know yet. I managed to remove my ABS unit and sent it off to ECU testing.They told me they had found a fault which they fixed [£200]. They returned it and I re-fitted it.
When I came to bleed the brakes I found that my rear anti roll bar link had departed from the ARB and repairing that has led to a chain of other things that I have decided to do whilst I have the rear up in the air and stripped down.[please read that as it is meant to be read].
Basically putting on new discs and pads,HEL brake lines,roll bar bushes and links,callipers and brake shoes plus a bit of cleaning up and rust treatment.
Bad weather has halted things for a while so I haven't been able to check if the new ABS unit has cured the warning light problem.
I will update as soon as possible.

Regards.

Oooof, you won't be selling the car in a hurry eh ! Not after spending all that.

 

[Lexybhoy]

Low, or maybe more correctly, lowered battery voltage can cause a multitude of these type of issues. If the car is road legal, ie. not sorned I would do as Dave suggested and give it a good run. Just be aware that although the brakes will work fine the ABS won't if the light is on.

Tony.

Hi @t-tony

you have echoed what my mechanic friend has said, given the car was garaged for a month, he said he'd charge it, drive it and then repeat at least once more before committing to any stripping work.

So on goes the charger tonight till Monday then if I can stay away from the new toy (Alfa 159) then I'll take it for a run on Monday afternoon. Weather permitting of course.

 

[Lexybhoy]

Two common problems here, one is easy, its a wheel sensor, change them, code reader will tell you which one. The other is the ABS/ASC control unit, it gets dry joints over time and needs repairing cost about £150.

The resetting of the lights should not need a code reader once the repairs are done, as this is one set of sensors on the car that goes through a diagnostic every time you start the car, if it finds no faults after a short drive (200 yards) the lights will extinguish.

Other things that can trip the abs / asc lights:

Uneven road surface
Dirty sensors
Incorrect toe on the front wheels
Wheel spinning and donuts
Incorrect tyre pressures or uneven across an axle
Worn suspension components
Coil pack or ignition system breaking down (The ASC works by cutting the spark to the engine as well as the applying brakes)

A combination of all the above.

All likely causes Zedonist, however both lights came on simultaneously, so I've got to think the cause is singular initially.

 

[Acousticplayer]

Hi Lexybhoy. Yes isn't it strange how one little thing leads to a whole host of other unintended things.Only wanted to put the drop link back on the ARB and ended up on a restoration job,not that it really needed it.Many on here will have experienced that I'm sure.
No I've no intention of parting with her,she's in my will and being passed on to my grandson.
Got a few jobs planned for this year.A custom exhaust and new hood and the sills need a bit of attention.All good fun though!
Regards.

 

[zedonist]

Both lights always come on together when there is a fault as both the ASC and ABS are intrinsically linked, if there is a fault with the ABS the ASC cant work, and if there is a fault with the ASC the ABS gets shut down, hence both lights and the reason you need to read the code, and usually it is a sensor that has tripped it or the ASC / ABS Module.

So once you know it is a sensor you need to try and find out what caused it to trip out, hence my list above, if it is not one of those then it is the sensor on its way out.

In normal working conditions a tripped sensor is just doing its job and telling you the system is wrong, not that the sensor is broken, so you can change sensors all day long and still have the fault. for example when I had this problem it turned out to be in the ignition system and not the sensor.

I think you are following a correct course of action though, low battery power on these old cars seems to wake the gremlins, so once fully charged, take the car for a spin the lights may go out. If not read the codes.

 

[Lexybhoy]

Both lights always come on together when there is a fault as both the ASC and ABS are intrinsically linked, if there is a fault with the ABS the ASC cant work, and if there is a fault with the ASC the ABS gets shut down, hence both lights and the reason you need to read the code, and usually it is a sensor that has tripped it or the ASC / ABS Module.

So once you know it is a sensor you need to try and find out what caused it to trip out, hence my list above, if it is not one of those then it is the sensor on its way out.

In normal working conditions a tripped sensor is just doing its job and telling you the system is wrong, not that the sensor is broken, so you can change sensors all day long and still have the fault. for example when I had this problem it turned out to be in the ignition system and not the sensor.

I think you are following a correct course of action though, low battery power on these old cars seems to wake the gremlins, so once fully charged, take the car for a spin the lights may go out. If not read the codes.

Brilliant Zedonist, thank you very much for your patience. Very much appreciated.

 

[Conrad]

So guys, I have a similar problem but mine is doing something additional. While I'b driving, the front right wheel will brake sporadically, release and then the dsc and brake lights will come on. Then, the car will drive with no problem but the lights will stay on. If I turn off the car, the system will reset (no lights) and I can drive for a day or so and then it will do the same thing again. Sometimes it does it twice in a day.
I took it to the shop and they replaced the YAW sensor which is under the driver's seat as that's what the computer said was bad. It was good for a day and then back to the same thing again. Can anyone provide some insight or guidance? It only happens in the one wheel.

 

[t-tony]

Assuming you're not pressing the brake, the only thing that can apply pressure to the brake line would be the abs pump? So my suggestion would be have it overhauled or replaced. Hope this helps some how Conrad.

Tony.

 

[Brian4]

DSC system has a separate charge pump in addition to the ABS pump and this is triggered by one of the sensors.
Mine had similar symptoms to yours @Conrad when the front wheel would shudder and then the DSC switch would stay lit. The ABS light didn't come on so it was just in the DSC system. Mine was the yaw sensor faulty probably from it being wet.
When yours was changed was it a new one if not perhaps the used one is also faulty.

This is the new one.$1100
https://www.ecstuning.com/b-genuine-bmw-parts/yaw-sensor/34526864094/

I would get the fault codes read again and see what it comes up with.

 

[Conrad]

Didn't pay $1000 so my guess is that it was used. Is there no chance of it being a wheel sensor? The shop is a little behind so they can't get me back in until the 11th. Was wondering if there was something I could do in the mean time.

 

[Conrad]

Assuming you're not pressing the brake, the only thing that can apply pressure to the brake line would be the abs pump? So my suggestion would be have it overhauled or replaced. Hope this helps some how Conrad.

Tony.

Tony ,
No foot on the brake pedal. This happens while I'm driving down the highway. Scares the *!#?! out of you.

 

[t-tony]

Tony ,
No foot on the brake pedal. This happens while I'm driving down the highway. Scares the *!#?! out of you.

Brian has probably hit the nail on the head Conrad, I wasn't aware that the DSC could do that to be honest but suggestions often prompt someone with more knowledge to help out. Is it possible you could get it code read some place else local, just to see if it is that Yaw senor again?

Tony.

 

[Conrad]

I have a friend at the dealer. Gonna see if I can call in a favor.

 

[bertiejaffa]

My 2.0l is just having the ABS module fixed at http://www.bba-reman.com/uk/index.aspx as we speak. AlanW has just had the same also - common issue with these cars along with the ABS sensors.

 

[Conrad]

So they held it at the shop for two weeks testing and making sure everything under the seat was dry. They said there were no faults. Drove it for two months and everything was good. I was super happy until last week when it did it again : (
I'm thinking I need the $1100 yaw sensor.....I think I can live with it for now. I have some other things I can do like getting my Eibach/Bilstein lowering kit installed. I can also get my Supersprint exhaust. An DSC fault every 2 to 3 months isn't that bad. I can live with that.

 

[N4LLY]

Had this same problem with my 120i. Break's were fine, but with the light on would not MOT.
Was the ABS pump. Managed to get refurbished for about £120.--