A6 Allroad 2015 C7 - Left Rear ABS Wheel Speed Sensor

[Loz D]

Hi All,

I completed a 2000 mile trip to France and Germany last week.  Whilst descending a snow covered mountain road, when I applied the brake, the ABS kicked in for a couple of seconds and a number of warning lights illuminated including traction control, DSC etc.  Fortunately I was only doing about 8mph so no real loss of control and managed to stop reasonably easy.  Finished the rest of the descent at less than 5mph.

Managed to stop and after turning the engine off and then back on a couple of minutes later, only the ABS Warning light remained illuminated.

A friend managed to check the codes for me last night (works for Audi) and the following error message was detected:

C101C07 Left Rear ABS Wheel Speed Sensor - Mechanical Malfunction.

My friend advised that it could be just a loose connectiom or something more challenging.

I have done some research online and there is a video on Youtube (Repairing a typical ABS Sensor fault on several Volkswagen, Audi and Seat models by MEYLE) that recommends a kit that overcomes this potential problem. It is allegedly common on VW, Audi and Seat.

I spoke with Audi Specialist who have quoted a price of ca. £500 to replace bearing, sensor etc to rectify the problem.

My thougths are:

1.  Could it be a simple loose wire on the sensor?

2.  As the Meyle video implies, is it just corrosion on the part that connects with the sensor that is the problem, the replacement kit will solve as claimed?

3.  As a matter of caution should the wheel bearing be changed?

Can anyone advise on their experience if they have encountered this issue on their cars?

Thanks in advance for any replies and suggestions.

Regards

Loz D

 

 

[Magnet]

Hello Lawrence,

Thanks for being in touch.

As a starter, I just wonder what your Audi friend recommends - ?? 

Anyway - fault with left rear sensor:- 

This could be a poor connection onto that sensor, or some debris on the sensor thrown up by the snow, so the first port of call would be to check there. 

If all appears reasonably sound, then the sensor may have failed - obviously necessitating renewing it. If so, I would only use Bosch if not using genuine VAG. They can be very difficult to remove. 

This may solve the problem permanently, but if the problem reoccurs then the signal to the sensor may be weak. This signal is generally generated by a weak magnet built into the hub, and if this is substandard then that’s where ‘replacing the wheel bearing’ arises. In reality, it’s not the bearing which is at fault and needs replacing, but the hub, which houses the bearing, so it’s a question of replacing the whole hub, complete with the bearing. 

If this ‘worse possible case’ turns out to be the problem, then I have used reasonably price Febi hubs to good effect - much cheaper than VAG, and seem to be OK. 

Have a look at the disc back plate if you need to change the hub - these can rust quite quickly, and may warrant replacing while you are in there. 

Kind regards,

Gareth.