ABS Light reset

[DRIVER]

Hi guys first post so be gentle ok, Ive got my ABS light up on the dash, got the dreaded MOT due soon and need to reset the light.
Is this a possible DIY job, (like service light reseting) or will I have to take to a garage to get the fault code cleared and also diagnose which sensor has gone U/S.
Im quiet happy to replace the sensor(s) myself but if I can Id like to know if there is a home mechanics tool for reseting the light.
Cheers for the help, if this site is any where near as good as the E30zone then its gonna be GREAT

[DRIVER]

Just one other thing, if I have to get the fault diagnosed and they clear the fault code without replacing the sensor(s) will the light come back straight away or at a later date.
Really need some answers on this if poss
cheers

[Mallard]

you cant delete the fault. but you can have it diagnosed

sometimes the tester says its the abs sensor, but its actually the control ellement (mostly e39 s)

we had an example where the guy came in to have a fault read out on the ABS

"its the front and rear left abs sensor" we said
"ok, change them then" was the guy..

well, we changed , and then went into the DME to clear the codes... couldnt fin´d the DME on the tester !! Car was gone

The ABS fault was still there though?

So we say,..

"it may be the rear wheel bearing" as the rear left is usually the "control" for all the other ABS sensors.

"Ok.. well if it has to be , then lets do it"

2 hours later,.. and the wheel bearing is off (rear wheel bearings are never fun) a quick swap, and back to the tester.

STILL NO DME !!!!

Now, the mechanic is starting to sweat..

He then comes in , with a face like a cats arse.. and says, "it could be the ASC box" which is the switch control for the ABS system (at £400)

well.. The customer got a very good price on the control box, and then everything was alright.. but it wasnt the right way to go in my opinion.

What this has to do with you , i have no idea, but hey Welcome to the Org

[Mallard]

back to the point

You will need a specific tester to fault read and clear, you cant do it on a regular service resetter.

You will also need to know which ABS sensor of the 4 is faulty, so its a diagnosis sadly.

All being well, a change of sensor and it´ll be good to go

[DRIVER]

excellent will be on line later on to have another snoop around but for now many thanks for the speedy reply back in a tick ok

[jordanmc]

I just got my car out of the impound =/ to find this ABS light on.

The car drives fine, brakes, handling, everything.

Is this something I should try to take care of?
Is there any danger of a very expensive repair if I dont get it looked at or reset?
What does this sensor do exactly?

[applefan]

I have the ABS light up on my 318ic also

As per the BMW user manual, it is just that ABS will not work when you use brake. Otherthan that, it is business as usual.

However, I just wanted to get rid of it to have a clean dash. I was wondering if anyone found a reasonable way to diag and fix.......?

[Mallard]

To Jordan,

The sensor reads marks on the edge of the wheel bearing hub as it rotates

these marks are matched for speed in the ECU of the ABS system. If the speed of a single hub rotate at slower speeds than the others, the car translates this as a slipping wheel under breaking (wheelspinning doesn´t throw an ABS action)

If the ABS unit cannot calculate the speed accurately, then the ABS lamp will switch on untill deleted. If the fail is still present after deletion, the lamp will return untill the fail is resolved

The Braking and ABS systems opperate seperatley, The ABS may not opperate in an emergency but the braking syst. will function wilthout problem

the ABS sensors are electro magnetic units the read the marks on the wheel bearing hub.


--

Applefan, the best way is to get the fail codes read out , and depending on the type of tester, which wheel the problem lies with. Then its a test again, and then replace said sensor.

[1lenny]

Mallard--Can we test the sensors for resistance, or continuity? I have a Peake reader, and I don't think it will show codes or which sensor. I'm having the same problem, and I've just replaced the ASC relay. I had a good ten minutes when I thought it was fixed.

[Mallard]

yeah you can measure the ohms frequency

the measurement should be

http://www.318ti.org/forum/showthread.php?t=14322

heres the shizza ,

[lpcapital]

The light itself should self reset once the fault get solved (I experienced that several times: once I forgot to plug back the sensor the other just today when I got the car on the rollers for the smog test and the junky forgot to off the traction control) . The code remain stored in the module but the light turns off. Carsoft clears the code from the ABS/ASC control module.

Most of the time the fault is with the wheel sensors, it happens that dirt and moist get in there and interfere with the sensor. Before buying parts, remove each sensor and clean it with some brake cleaner or electric contact cleaner. That solves the problem most of the times.