ABS fault?

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zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

ABS fault?

Post by zgeekster » Thu 20 Apr, 2017 20:56

Hi

I'm a newbie here, but have had my Z3 for a year now. I believe the previous owner had a blog on here calling it 'Cinders'.
Its been great, no real faults, until the ABS and traction control light came on, oddly just after I had jacked up the right rear to check the exhaust. So I had been convinced that I had moved the harness for the right rear ABS sensor. A battery disconnect cleared the fault for a few minutes, but now its always on.

I bought a C110 reader.

Initial code for P0500 speed signal could be erased , no problem.

It also had 14 Front Left and 41 Rear Right. But oddly 78 Battery Voltage. But the battery is 12.4 v. (Actually, come to think of it the warnings came on before i put a new battery in)

New sensors were fitted by the previous owner.

Faults cannot be erased at all.

I took the ABS ccontrol module off, just to check for corrosion. Couldn't see anything obvious. All pins look good. Put it all back together.

Now I have codes 14 and 41. But 78 has gone, replaced by 71 ABS PUMP.

The codes cannot be deleted at all. i.e it does not require driving with a lack of signal from the wheel sensors to trigger.

So.....what do you good people think? Replace the ABS control module, as a first step? Its actually cheaper than buying a sensor (for a known ok second hand one)

I really want to look inside for dry joints!

Many thanks

Geekster

John Wilson
Joined: Fri 12 Jun, 2009 13:11
Posts: 240

  Z3 roadster 2.0
Location: Diss

Re: ABS fault?

Post by John Wilson » Thu 20 Apr, 2017 22:03

Before you do all that, have you tried cleaning all the wheel sensors. It should be easy to do if they have been replaced. Just one bolt each one with an allen key. I used to have regular problems with my ABS light years ago when I first got the Z3. Now I clean the sensors once a year and never have a problem now. After you do them, the light doesnt go off straight away. It takes a couple of journeys.

zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

Re: ABS fault?

Post by zgeekster » Thu 20 Apr, 2017 22:26

Hi John

Thanks for your reply; much appreciated.

OK, I'll have a go at cleaning off the sensors - I'm just waiting for the locking wheel nut key to arrive so I can get the wheels off ( my small boy child was 'helping' a while back and put the key in the wheel bolt without telling me - its somewhere in a north london gutter!)

I found a module for £25, exactly the right part number, so I have ordered it any way, just incase.

I will feedback with results for reference.

zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

Re: ABS fault?

Post by zgeekster » Sun 23 Apr, 2017 21:51

Update....

I cleaned the sensors; right rear was fine. However, the left front was not so pretty, basically it had its end ripped off by a bit of the heat shield!
I managed to get a new sensor and fit it with no issue.

ABS and traction light still on. Fault codes still present even after trying to delete, a drive of 4 miles and a battery disconnect over night.

New ABS unit should be here tomorrow. I'll give it a go.

If its still no good is there anyone near North London, Barnet with better diagnostics?

Also, I'm going to need two new front quarters, strut, knucles, calipers, lower arms. Its all a bit of a mess under there! Any decent breakers out there?

zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

Re: ABS fault?

Post by zgeekster » Mon 24 Apr, 2017 20:57

Argh....

New controller arrived, put it on...

Pump fault has gone, but still got the right rear and left front codes. Plus, as an extra little bonus; 76 Electrical Interference to speed signals.
This was all when stationary. 3 mile drive and still the same.

I suspect a harness issue...do the Left Front and Right Rear share and common feeds?

Are there circuit diagrams and layouts available anywhere?

Thanks in advance!!

zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

Re: ABS fault?

Post by zgeekster » Mon 24 Apr, 2017 21:11

Woo hoo

I found the wiring diagram on the Knowledge base.

Z3 ownership seems to be a rollercoaster of emotions!

bertiejaffa
Joined: Fri 26 Jul, 2013 10:28
Posts: 1725

  M roadster S50
Location: Manchester

Re: ABS fault?

Post by bertiejaffa » Mon 24 Apr, 2017 21:41

Stick with it - it can be a steep learning curve initially but theres plenty of info on here to get you through...

Welcome btw
Here come the girls.....
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My First Zed Journal

DanHolman
Joined: Sun 10 Jul, 2016 11:43
Posts: 42

  Z3 roadster 1.9

Re: ABS fault?

Post by DanHolman » Sat 29 Apr, 2017 20:04

Something obvious may have been overlooked- You say new sensors were fitted by the previous owner, do you know if they were genuine BMW OEM? or were they bought on ebay for £10 you know what I'm saying? This may be the source of your problems.

zgeekster
Joined: Wed 19 Apr, 2017 08:25
Posts: 21

  Z3 roadster 1.9i

Re: ABS fault?

Post by zgeekster » Sat 29 Apr, 2017 21:32

Update....

I tried to use a multimeter reading AC V to on all the ABS signals, but got nothing.
So I kust went for resistance measured at the ABS plug. Rear Right was open circuit, all the others were about 1kOhm.
Turns out that one of the pins was bent on the sensor. It was fine before, when i checked, so it must have been me just BEFORE fitting the new ABS unit.

Tried to straighten it out, but as it wasn't an OEM part I couldn't disassemble the harness connector (its an over moulded type rather than push in pins and proper seals). The pin broke, obviously - I even had my wife trying to do it more delicately than i could.
Anyway I managed to build a new connector up by drilling out the back end and splicing in pins from the broken front one I had. Water proof heat shrink and sealer, and it plugs in fine, and can be un plugged too.

Light out.
ABS working beautifully.

Still had codes in my C110+ though, which is odd. They may have gone now...

So, in conclusion there were two initial concerns...
1. Mullered front senor
2. I am sure the ABS controller was broken, giving faulty pump

And then...

3. I am a hamfisted moron and bent the rear pin (but i was convinced months ago that the pin was misaligned, the previous owner has force the pin to make its own new hole in the female part of the connector)

Oh, and

4. The ABS faulted with a very low battery, which never helps.

I hope my woes help others!?

My daughter and I fitted a new rear screen today too; it only took 15 mins to zip in.

Its getting there, slowly!

yme402
Joined: Sat 25 Jul, 2015 20:22
Posts: 15

  Z3 roadster 2.2i

Re: ABS fault?

Post by yme402 » Fri 05 May, 2017 20:49

I appear to have a similar issue. This has only just started today and both will light up on one journey, but will be gone on the next...so very intermittent. any suggestions?

mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 803

  Z3 roadster 1.9

Re: ABS fault?

Post by mrscalex » Fri 05 May, 2017 21:42

If I remember rightly the 78 battery issue is caused by a flat or removed battery.
ImageImage
1999 Z3 1.9 Boston Green (Dimitri) - My brother's car owned from new and restored by me
2001 Z3 2.2 Topaz Blue (Trudy) - My car rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Okus) - Project car waiting for a new engine
2001 Z3 2.2 Topaz Blue (Debra) - Donor car/breaker
1998 Z3 1.9 Boston Green (Allsworth) - Donor car/breaker now gone to Z3 heaven
Always happy to try and help with spares :)

gookah
Z Register member
Joined: Thu 07 Aug, 2008 10:51
Posts: 2727

  Z3 roadster 2.8

Re: ABS fault?

Post by gookah » Fri 05 May, 2017 21:56

yme402 wrote:I appear to have a similar issue. This has only just started today and both will light up on one journey, but will be gone on the next...so very intermittent. any suggestions?
You will need to get the codes read.. the faults will be stored...
Image

Z3 2.8 Progress Journal (Mine)
Z3 1.9 Sport Progress Journal (Wifey's)

I have an element of 'M-styling' on my car, If that's a good enough reason for the manufacturers to adorn a 320 with the M badge, then its certainly a good enough reason for me..

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