It's fixed!! (I think)
During the week I don't have time to work on the car because of work and a little Gremlin wanting attention. But I ordered stuff online so I could get around fixing stuff today.
First things first, what I did was clean the connectors as @Jfgoldfish mentioned. Now I don't have the tools to "un pin" the connectors I did have plenty of contact cleaner and a compressor and a dental pick, so I cleaned the connector the best I could and hoped that this wasn't the issue.
Next up, do a complete flush of the braking system. Getting the car on jacks was new for me, but in the end, it's just really easy. Many thanks to all the people who have written the DIY's and YouTube videos.
So the car is on jacks, wheels are off. I then removed as much brake fluid from the reservoir as i could using a syringe with a long nose. Got most of it out and a small syringe for the last bit. The colour is best described as dark brown. Then attached a brake power cleaner (got one with a 3 liter reservoir) and filled up with about 1.5 liters. As and advice, I saw on youtube that there is a hose without a clamp attached to the brake reservoir, to make sure this hose would not jump off and splatter brake fluid everywhere I used a tie-rap to close attach it more snug. Pumped up the brake power cleaner to about 1.8 bars of pressure and set to work. Drained all the fluid until my nice clear yellow was running through the cannister line. Pumped the brakes a couple of time in between, and moved the steering wheel from side to side. After all this was done, cleaned up the engine bay of any drops spilled and used water to rinse things. Get the tyres back on, and put her down on the ground.
#note: this sounds very easy and the tutorials on the internet make it look like a hour job. I took me all by all about 2 hours with checking for leaks, making sure that everything was nice and tidy, cleaning up and drops I might have spilled.
Next up, coding the DSC unit with NCS Expert. A proper guide can be found here
https://www.bimmerforums.com/forum/attachment.php?attachmentid=414523&d=1342141550 just change to the E85 system and look for the DSC module, follow the steps.
Time to clear all the errors and reset the sensors using INPA.
Then ran the car, but the error light came back after about 10 min, still giving me a 5E21 Druck Sensor 2 elektrisch defekt. Next step was to remove the wire harnass of the DSC sensor in the engine bay and see if it was the sensor or the DSC computer module or maybe a wire issue or just the DSC sensor.
And then it happened! It gave me a fault code that sensor 1 was not working!! I just unplugged sensor 2 according to all the internet pictures. The only possible explanation, the previous owner must have had work done to the car and it wasn't put back the way it was meant. So I grapped a new DSC sensor and with a lot of patience I was able to remove the real sensor one and install a new one. lost a couple of drops of fresh brake fluid. I do have to mention this was not the easiest job, not because it's technical or difficult, the issue is the size of my hands. I could barely reach the unit. Yet after about 20 minutes of fiddeling around and considering amputating my thumb the sensor was back in it's place! I then cleaned the connector as I had done with the DSC computer and attached everything.
Booted up INPA, reset DSC sensors again, cleared the steering wheel offset and the DSC errors and took the car for a drive and that was the last I have seen today of the errors!!
So in short:
- Clean all connectors
- Brake fluid flush
- Double check that someone has not switched the DSC Sensor cable
- Replace broken DSC sensor
Or at least I hope!! Did drive for about 30 minutes without any errors on the dashboard.