[dgilson]

2011 2.0d xDrive SE auto, 75,000 miles. Recently, I got the same error messages and dire warnings as the OP, (must be something in the West country air). So was very pleased to find this thread, and to learn that the culprit might be nothing worse than a faulty wheel speed sensor. Many thanks to plymjack for posting.

For anyone interested in the DIY approach, I hope the following may help.

Replacing the sensor is fairly simple, but first you have to find which one is faulty - not so easy, as I found.

Removing the sensors They’re a bit fiddly to get at, a torch may help. First remove the wheel. The sensor head is held in the hub by a single screw (5mm hexagon key). Ease the sensor from its socket with care. Release the cable from the various clips and restraints. Its electrical connector is housed in a protective black plastic box, which may also house the connector for the brake pad wear sensor.

On rear sensors, the box was obvious and easy to get at and its lid unclipped at the bottom. On front sensors the box was hidden behind the wheel arch liner and I had to undo several liner fixings - 3 plastic nuts (10mm) and 4 screws (8mm), and flex the liner quite a lot. In this case, the lid unclipped at the top. A torch and mirror definitely helped. On re-assembly, ensure the liner is correctly located over the studs for the nuts before inserting any fixings.

Testing the sensors Searching the web produced some ideas for testing which involve disconnecting the sensor at its electrical connector and attaching a multimeter across the two sensor pins. You either do a diode test (didn’t work for me), or measure millivolts when you rotate the wheel (inconclusive for me).

I spent a long time faffing around at this and managed to convince myself that the right rear sensor was faulty. So I replaced it, but the error messages persisted…….

So I needed help. The good guys at my local garage (a general workshop, not a BMW specialist), plugged their diagnostic equipment into the vehicle and quickly established it was the right front sensor that was faulty. I replaced it, and the error messages and warnings went away, once I’d driven a few yards, and they haven’t returned since. (I gather that the error codes remain within the system, so I made a return visit to get them removed).

The right rear that I first replaced may or may not have been faulty. I’ll keep the original as a possible spare, anyway.

Overall I would say it’s not worth trying to test these sensors yourself, just find someone with the right diagnostic equipment to identify where the fault lies, before starting any DIY.

A final word on sourcing the sensors Realoem.com lists them under front and rear suspension, and it calls them “dxc pulse generator”, which is a bit confusing. Front and rear have different part numbers.

None of the usual motor factors stocked them for this vehicle. Buycarparts.co.uk offered them at a very favourable price, then decided they could not supply me, but they did eventually refund my money.

In the end, I used BMW supplier cotswoldgroup.com. Online price for the rear sensor was £83 including delivery, front sensor £90 incl delivery.