ABS sensors

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   My E39 seems to be jinxed at the moment! About 2 years ago a new n/s ABS sensor was fitted. About 6 months ago, the car was in my local indy for a different job, and I asked him to check the ABS, as the light had been coming on occasionally. He said the n/s front ABS signal had logged a code for a dodgy signal - I told him the sensor was relatively new, he said it could be the wheel bearing in that case, as the reluctor is built in.

i didnt do anything about it at the time, and left it until a few weeks ago, and had teh bearing changed - fault the same. I thought - sensor - so I replaced the n/s/f sensor. Now the dash light are off, but the traction control kicks in whenever I first drive off, so I have to turn it off, and whnever I touch the brakes the ABS kicks in, until the ABS realises something is wrong. and puts it out of action. At the same time the autobox is now playing up, it will only shift up to 2nd or back down as the speed drops, I have to change up manually - so what on earth is going on??

Some have suggested the n/s/r sensor is failing - but no problems with the speedo, which I believe is driven from the n/s/r sensor.

I realise i am going to have to take it in and get the codes read I suppose - more expense no doubt!!    

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RICHARDD Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 03 Feb 2008 Location: United Kingdom Status: Offline Points: 43	Post Options Post Reply Quote RICHARDD Report Post Thanks(0) Quote Reply Topic: ABS sensors Posted: 22 Mar 2009 at 5:20pm
	My E39 seems to be jinxed at the moment! About 2 years ago a new n/s ABS sensor was fitted. About 6 months ago, the car was in my local indy for a different job, and I asked him to check the ABS, as the light had been coming on occasionally. He said the n/s front ABS signal had logged a code for a dodgy signal - I told him the sensor was relatively new, he said it could be the wheel bearing in that case, as the reluctor is built in. i didnt do anything about it at the time, and left it until a few weeks ago, and had teh bearing changed - fault the same. I thought - sensor - so I replaced the n/s/f sensor. Now the dash light are off, but the traction control kicks in whenever I first drive off, so I have to turn it off, and whnever I touch the brakes the ABS kicks in, until the ABS realises something is wrong. and puts it out of action. At the same time the autobox is now playing up, it will only shift up to 2nd or back down as the speed drops, I have to change up manually - so what on earth is going on?? Some have suggested the n/s/r sensor is failing - but no problems with the speedo, which I believe is driven from the n/s/r sensor. I realise i am going to have to take it in and get the codes read I suppose - more expense no doubt!!
	If in doubt when all else fails - read the instructions!!

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Ian Arthur Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 03 Aug 2007 Status: Offline Points: 313	Post Options Post Reply Quote Ian Arthur Report Post Thanks(0) Quote Reply Posted: 22 Mar 2009 at 6:58pm
	at the risk of sounding stupid(which i am) i had a simlair fault on a e46 recently,turned out it was a blown fuse..........cant remember for the life of me which one, maybe worth checking the simply things first

Cabrio Members Profile Send Private Message Find Members Posts Add to Buddy List Register Chair E30 Register & Competition Secretary Joined: 24 Aug 2006 Location: United Kingdom Status: Offline Points: 6625	Post Options Post Reply Quote Cabrio Report Post Thanks(0) Quote Reply Posted: 22 Mar 2009 at 7:09pm
	Hi - do you know age of speed sensor and the ABS control unit as these cause ABS and DSC issues
	E30 Register joint coordinator - Competition Secretary - Contact name Neil for PM and Email - cabrio_e30@yahoo.co.uk - be aware addicted to E numbers

RICHARDD Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 03 Feb 2008 Location: United Kingdom Status: Offline Points: 43	Post Options Post Reply Quote RICHARDD Report Post Thanks(0) Quote Reply Posted: 23 Mar 2009 at 10:01am
	The car is an S reg 1998 model, I dont know the age of the ABS unit - but probably the original - nothing in the history about a replacement, and again nothing that I can recall about the rear ABS sensors. Changing the wheel bearing and the n/s/f sensor created different faults, and seems odd that the sensor renewal caused the autobox problem - unless just co-incidence of course. All these gadgets are great - when they work!!
	If in doubt when all else fails - read the instructions!!

Cabrio Members Profile Send Private Message Find Members Posts Add to Buddy List Register Chair E30 Register & Competition Secretary Joined: 24 Aug 2006 Location: United Kingdom Status: Offline Points: 6625	Post Options Post Reply Quote Cabrio Report Post Thanks(0) Quote Reply Posted: 23 Mar 2009 at 10:46pm
	Hi the ABS control units do give trouble and will affect ABS and DSC depends on Bosch number as to how easily to replace - but can be repaired....unfortunately to avoid replacing loads of bits on guess work may need dealer equipment and a decent reliable technician - not great news I know - got similar problem on a 540 E39 currently and comes on and off 99% certain I know what it is but new part is too expensive so waiting for good used off 540 or 740 or get it repaired - but cant diagnose yours on info provided
	E30 Register joint coordinator - Competition Secretary - Contact name Neil for PM and Email - cabrio_e30@yahoo.co.uk - be aware addicted to E numbers

RICHARDD Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 03 Feb 2008 Location: United Kingdom Status: Offline Points: 43	Post Options Post Reply Quote RICHARDD Report Post Thanks(0) Quote Reply Posted: 24 Mar 2009 at 9:26am
	Thanks Cabrio - I hope it isnt the ABS unit!! Anyway it is booked in for a look see this Friday,. so we shall see. Another forum suggested that the n/s/r ABS sensor can partly fail, so that it still gives the speedo information to work, but can corrupt ABS, ASC and autobox signals. Quite how that can be, beats me as there are only 2 wires to the sensor, which I would guess is like a hall sensor, so I would have thought it eaither worked or not. But then my knowledge of electronics is limited!!My feeling is that it is a sensor though, as changing the wheelbearing did nothing, but changing the n/s/f sensor put the ABS and ASC light out on start up - but then caused the ASC to cut in unless switched off manually, and the ABS to cut in from start up when braking, plus it also stopped the autobox shifting, so in my view it could still be a sensor (hopefully) Maybe the n/s/f sensor is a dud - it wasnt a genuine part it was GSF. As I said before, all these gadgets are wonderful - when they work, and tend to be damned expensive when they dont!! Richard
	If in doubt when all else fails - read the instructions!!

RICHARDD Members Profile Send Private Message Find Members Posts Add to Buddy List Club Member Joined: 03 Feb 2008 Location: United Kingdom Status: Offline Points: 43	Post Options Post Reply Quote RICHARDD Report Post Thanks(0) Quote Reply Posted: 10 Apr 2009 at 9:35am
	Car now fixed! It was the GSF ABS senosr I had fitted - it gave a good signal up to around 5mph and then broke up, causing all the problems. My local Indy had the car for 2 days, along with 3 other cars with ABS faults, as he wanted to get to the bottom of all the problems, as he has had ongoing issues with all of them. He had used a variety of ABS sensor suppliers, including GSF, Euro Carparts etc, and had problems with all of them, generally just not lasting very long, or not working at all sometimes. He naturally tries to keep prices down where possible to help his customers, but after this episode, he will now only fit genuine BMW sensors (Siemens) as this is the only way that he can be sure of fixing the faults. Not cheap of course - but I am glad to get it all working properly again. So my advice to anyone with ABS problems - is to get the codes read to find out which sensor is the faulty one, and only fit genuine sensors as a replacement. Richard
	If in doubt when all else fails - read the instructions!!