Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light

Honest John Back Room » Technical matters
View Threaded
Mon 24 Jul 2017 17:59
Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light - Poacheruk

OK, heres what happened.

Pulling into the end parking slot in B&Q's car park, the front passenger side wing bottom scraped the kerb. This ripped of the inner wheel arch liner, and in the process pulled the blue ABS sensor plug and socket apart. the liner ended up under the wheel

Having restored the wheel arch liner, I now have the ABS light on. Ive had a good look at the blue plug and socket, it hasnt damaged it but it was forcibly pulled apart. It plugs back together with no obviious problem. All the rest of the wiring seems intact. The wiring as it enters the wheel hub assembly is tightly attached, so it cant have pulled the wire out the sensor. The fact that the ABS light stays on is baffling.

I did some googling, and i can confirm the speedometer still works. I dont know if the ABS actually still works. What can I do from this point?

How do i test the wheel sensor? Could the wire have been stretched and broken internally between the main loom and the sensor? Where do I go from here?

Any suggestions gratefully recieved.

Steve

(Edit) Somone suggested this is an error light that doesnt go out when the fault is cleared, you have to plug in a code reader and clear it manually. IS this the case?

Edited by Poacheruk on 24/07/2017 at 18:24

Reply | Report as offensive | Link
Mon 24 Jul 2017 19:31
Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light - elekie&a/c doctor
If the light is on,then the abs is not working.If all the wiring is good and intact,you are going to need diagnostic kit to reset the system.These are active abs sensors on this,so not easily testable

Edited by elekie&a/c doctor on 24/07/2017 at 19:33

Reply | Report as offensive | Link
Mon 24 Jul 2017 19:36
Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light - Poacheruk

Thanks for replying

It all worked fine before the incident. The only possible thing I can think of that could have occurred is either a) the sensor has been damaged or b) the wiring is broken internally.

However testing the wiring would involve cutting the section out and testing with a multimeter, and if ok soldering it back in. This seems a bit drastic and last resort. Might be eaiser to try and reset the error code first, see if it reoccurs?

Is there not a simple continuity test to make sure the wires to the sensor are intact? What should the resistance of the sensor be?

Steve

Edited by Poacheruk on 24/07/2017 at 19:38

Reply | Report as offensive | Link
Mon 24 Jul 2017 19:47
Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light - elekie&a/c doctor
It is not possible to check the sensor resistance,it is electronic and does not have any.It is possible to test continuity from the abs module to the blue sensor connector,but access to the abs module connector is almost impossible without major surgery.I would go the diagnostic route first.If you know anyone with Bmw test kit,very often you can access the systems on the 75 by entering the obd system as a Bmw 5 series E 39 series.
Reply | Report as offensive | Link
Thu 27 Jul 2017 13:41
Rover 75 CDTI BMW engine 04 plate - Rover 75 ABS light - Cyd

Use wire piercing probes on your DMM to check continuity of each wire along it's route

OR

Pierce each wire with a fine sewing needle and work your way along it's length that way. Rub some silicon sealer in the pin holes after or use some shrink wrap tape (don't use PVC tape)

Test the sensor by connecting across it's terminals with your DMM set on mVAC. Turn the hub by hand and you should see a small AC voltage generated. Try this method on all the sensors to be sure it works and see the reading level you should be expecting (and you never know, it might be another sensor that has failed quite coincidentally)

My son's Polo had a frustrating ABS fault. Turns out there is a fuse box on top off the battery which isn't mentioned in either the owners manual or the Haynes. Make sure your car doesn't have something similar. https://youtu.be/0YCg1DMBOWo?list=PLOaePmzqZNJ0toh4O7gjSCiKEix0odCq-

Once you have fixed the fault(s), the ABS light will reset itself once you drive the car at 8+mph (also like the Polo - many claim it can only be reset with VAGCOM)

Happy hunting.

Reply | Report as offensive | Link