Replacing the Steering Angle Sensor

[R515]

Replacing the Steering angle sensor (SAS)

The following worked for me but use this guide at your own risk

This module is referred to as LEW in my version of DIS and LWS in NCS

Replacement of the above component became necessary after regular illumination of the Amber DSC light on the instrument cluster. This usually occurred when pulling away and turning right after a give way or stop junction requiring a good pull down of the steering wheel.

Diagnosis by DIS always showed this to be an internal error within the SAS and the diagnostic plan stated was to replace the unit. First off though I tried the recalibration process and this seemed to work for a day or so before the fault came back so replacement was going to be the long term solution.

I was able to source a new part of the correct part number according to Real OEM from Germany via e-bay for about half the price the main dealer wanted and this arrived in a couple of days so well done to that supplier.

Replacement requires the removal of the two lower trim panels beneath the steering column and then undoing and removing the pinch bolt that holds the two halves of the steering shaft together. This is far more awkward than TIS suggests as the steering wheel needs to be rotated to different positions to firstly remove the nut and then to remove the bolt itself. When you have done that, the section that the pinch bolt passes through will need prying open slightly to enable the steering shafts to slide apart, but, before pulling the shafts apart, make sure the steering wheel is straight. I didn’t and then had the problem of lost alignment between the steering wheel and the road wheels which was not helped by the very fine gauge splines where the two halves join together. I’ve taken steering columns apart on other makes of vehicle and not had this problem as they will only go back together one way but alas our beloved BMW’s are different.

With the two halves apart, the old SAS can be removed by just pulling off and the new one fitted. There is a locating pin that needs to pass through a slot in the sensor but fitment is fairly straight forward. Then it’s a case of joining the steering shafts together again and rotating as necessary to fit and tighten the pinch bolt and nut. Don’t forget to plug the new unit in and cable tie the loom as necessary before refitting the two trim panels.

Next the new unit has to be coded and calibrated. I coded it using NCS Expert and there are plenty of guides out there to show you how but for me, that’s bit I’m least comfortable with as I haven’t been brought up with computers. Previous to this, I had changed some options such as enabling the indicators to flash when the car is locked and disabling the auto door locking after driving off but still regard myself as a coding novice. I found a guide on the net about coding a used instrument cluster and this helped, in fact coding this new SAS was simpler and less daunting than making changes to existing modules.

Of note and before removing the old SAS, I read the LWS trace file in NCS Dummy and saved it just in case, I also made a written note of which boxes were ticked in this module, it’s very small by comparison to say the GM module so this was an easy task and enabled me to satisfy myself everything was okay after coding. After coding, I read the new LWS trace file and it was exactly the same as the old which was a good confidence boost.

After coding, the new unit has to be calibrated and this is done in the service function of DIS and is very straight forward

Finally clear all fault codes and enjoy no more DSC lights!