I would presume this is an E38 (rather than E36)fitted with Bosch ESP1.24.The pressure sensor is screwed into the hydraulic modulator body and monitors fluid pressure from master cyl.(3 pin connector).This switch is available as a seperate part at around £80 ,if I recall.However I have had issues with the main abs controller at fault giving the same dtc.Can you read any live data brake pressure with the Solus?Btw,same switch is fitted to some Vw Passat and Ford mondeo variants with esp.