Parking Brake / ABS error - but no fault codes

[sndrup]

Hi! Long time lurker, first time poster -

2006 E65 750i

Problem Description:
I got an ABS error while driving (5F0F DSC: Rotation-rate sensor, undervoltage). Cleared it, seemed to be running fine.
A few days later, the dash says, "Parking Brake Fault", then ABS error with dash message, "Brake/drive malfunct.! Drive moderately"

Troubleshooting:

1. I tested the parking brake and it's fine - it engages, disengages. Opened up the parking brake module and I can see it actuating just fine. 3 or 4 months ago I replaced the broken plastic gear with a steel replacement, and that seems to be working.
2. I run ISTA+ and there are no parking brake faults, no DSC faults - just errors for busted CD cassette and fog sensor. The 5F0F fault never returned after I cleared it.
3. Using ISTA+ I ran the only test I could find for EPB in calculating the number of rotations of the screw and it was within tolerances.
4. I attempted a parking brake reset - press & hold 5 seconds, repeat 4 times - and a few variations. No change.
5. Using ISTA+ I checked live feed data from the DSC module and all data points I could check seemed to have good data - all 4 wheel sensors, brake fluid pressure, etc. Only ones I couldn't test were lateral movement and yawl - I figured I'd probably have to do some donuts to test those so skipped it. No faults for DSC.
6. I did a chat session with one of the vendors recommended in this forum for doing DSC module rebuilds. They basically said that if there's a problem in the DSC, there should be an error code.
7. The only other thing I found was a small leak in the expansion tank which dripped down on the DSC module cable connector. The inside of the connector is perfectly dry. Fixed the leak, let it dry for a couple days just in case there was some chance there was as short, but no change.

Any hints? I'm to a point where I will prob have to take it down somewhere and pay for some diagnostics. Or I cross my fingers and get the DSC module rebult and hope that clears it up, but I don't really want to do that if I can't confirm that's the problem.

[sndrup]

So, I've had the DSC rebuilt, replaced the yaw sensor - and this is still happening. While driving every 5-20 minutes, I'll get a chime, the dashboard will light up and it will tell me "Brake and drive control systems malfunction. Parking brake without emergency braking function. Avoid hard braking..." Then the error will go away after 2-5 minutes.
I check codes when I get home, none are active. They are:
2DD9 No message, receiver DME, transmitter ARS
5F0F DSC: Rotation-rate sensor, undervoltage
Thoughts anyone? Thx in advance.