bmw ABS LIGHT ON AND NO SPEEDO?? Please help

[Samo121]

Hi I’m new to posting, had my BMW 3-Series parked up now for a year as Ive had a company vehicle. Desided to get it back up and running again now but as soon as I start the car I’m getting abs light on dash without moving . Also my speedo is not responsive at all . Scanned it the other day and have these fault codes but will not clear them? Any advice would be great thank you. Please see photos 

[Bimmer Owners Club]

Hi Sam

Had a similar incident with my Bimmer recently, but put it down to coincidence as it had also been laid up for some time.

However, I would be tempted to reset the battery and take it for a drive to allow everything to settle back in....if still has codes then (after clearing codes) then it would require further investigation.

Let us know how you get on with it

[Samo121]

Thanks for your reply ile disconnect the battery later and take it for a run. And post back this evening.Thanks 

[Samo121]

Hi just a little update had the battery disconnected for 10/15 mins and had a little drive in it. Still the same with the abs light on. Asked around today been told to remove the rear 2 sensors and clean Also spray wd40 or simalar down the sensor hole an spin the wheels. Is this linked to Speedo and abs or both ? Should this be attempted.? Thanks  in reply 

[Bimmer Owners Club]

I'm not sure that spraying WD40 will do much, except for the sensor connections which may have some corrosion on them.

I replaced the rear sensor on my Z3 for a grand total of £13.86 and it did the trick after a reset and short drive.

I was able to scope it and measure resistance to ensure it definitely was U/S and then purchased a replacement....didn't want to spend even this small amount unless I was sure it definitely was faulty.

If you can measure your sensors then if open circuit, replace it.

[Samo121]

Hi yeah I just give it a try any way and I’ve tested both rear sensor sensor I’m getting cotenuaty from then both I’m getting around 1.031 but when I spin the wheel and check for ac voltage I’m getting nothing at all from both rear wheels. Do these sensors look ok to you as I carnt see much of the magnetic strip? Think I’m going to get 2 rear sensors this week. Thanks for reply 

[Bimmer Owners Club]

The sensor readings are fine...maybe clean them up, refit and road test....it would be good to also try scoping it to see if there is any waveform produced

[Samo121]

 

Hi thanks for the reply I’ve had it on the diagnostic yesterday for some live data when driving and I’m not getting nothing at all from both rear wheels. I’ve removed the sensor cleaned them and Checked the ring in the hub for damage all looks ok? I am waiting for the new sensor to arrive it should be here tomorrow. Just a question if the sensor has contenuaty could it still be faulty ? Thanks ile update tomorrow evening 

[Greydog]

Morning Sam

If your sensors are OK and there is no change with your new sensor fitted, there could be a fault in the loom or the ABS unit could be faulty. I would be looking towards the ABS unit, there are several repairers BBA Reman, ECU Testing, Autotronics, ATPelectronics to name a few. I have used BBA and Ecu in the past with 100% success both businesses offered an exchange unit 24hr turn around.

I hope you get to the bottom of the issue

Dave

[Samo121]

Morning thanks for the info if there is no change with the sensor ile look into the wireing do all sensor wires run up to the abs unit ? Anyone have a diagram of the abs unit plug ? If no joy looks like abs unit will have to get chanced. Will keep you posted thanks 

[Samo121]

Replaced drivers side rear sensor Andy now the speedo is working. But still got the abs fault. Scanned today and no data coming from passengers side rear now so hopefully it will be the sensor on that side too. Just order another will update soon as I replace thanks