Intake Cam Sensor Replacement for E39 with M52TU
(Based on 2000 528i experience)
Time Estimate
Allow one hour the first time.  It will take much less the if you have to do it again.
What You Will Need
Be sure you get a new o-ring to go with the new sensor.  It is a good idea to have a new o-ring for the VANOS sensor too.  The original sensor retaining screw is installed with a drop or two of blue Loctite.  It’s your choice to use it or not.
Tools you will need are a 5mm hex key (Allen wrench) or ball driver and a 32mm (1-1/4”) open-end wrench.
The intake cam position sensor (cam pulse generator) is located on the driver’s side of the bottom of the cylinder head near the front.  The sensor is in close proximity to the oil canister cap and the cylindrical silver-color VANOS solenoid.location
Gaining Access
Removing the oil filter canister cap is not required, but it will make the job a little bit easier.  Consider including an oil change if you are close to doing one anyway.  I left my cap in place.  It probably cost me all of ten minutes.  Removing the filter cap requires a good six-point 36mm socket.
Separate the rigid plastic crankcase ventilation (PCV) system fitting by squeezing the top and bottom of the fitting’s plastic ring and pulling out the mating elbow.
Separate the electrical connector on the VANOS solenoid by pushing down the spring and pulling out the connector.  Next, unscrew and remove the solenoid.  Be aware that some oil(half a cup or less) will come out of the solenoid hole.  It is a good idea to stuff a shop towel in the space underneath the solenoid to absorb and prevent the oil from flowing onto the rest of the engine.
VANOS solenoid
R&R the Intake Cam Sensor
Follow the cam sensor pigtail and you will find its connector buried under a bunch of hoses and wire harnesses.  The connector is barely visible, but can be reached from the driver’s side by sliding your arm between two intervening hoses.  Again, push the spring down and pull on the pigtail side to separate the connector.
connector location 
Remove the Old Sensor
Unscrew and set aside the socket head sensor retaining screw.  This is the part of the procedure where removing the oil filter canister cap would help, but it is certainly not necessary.  The cap limits direct access to the screw.  I could not fit a socket handle with hex socket into the space available.  I found that a 5mm hex key worked fine, but it was slow going until the screw was loose enough to rotate with my fingers.  A ball driver may give you enough angle to use it instead.  Wiggle and pull the sensor out.  Expect no oil this time.
sensor removed
Coat the sensor o-ring with a light layer of motor oil and slide it down on the sensor.  Snake the pigtail attached to the new sensor roughly into place.  Slide the sensor into its hole while trying to loosely align the retaining screw holes.  Push the sensor in until its face is fully seated.  Rotate the sensor as necessary to align the mounting holes.  If you have blue Loctite, now is the time to apply a drop to the screw threads. Insert and tighten the retaining screw.  The holes are a pretty close fit.  Be sure you don’t cross-thread the screw because you have the holes misaligned.
screw with Loctite 
Replace the VANOS solenoid.  Lightly oil the o-ring first.  Mate the solenoid connector.  Finish routing the cam sensor pigtail so that there is no stress or potential chafe on it and mate the connector.  Push the PCV tubing connection back together.  Reinstall the oil canister cap if it was removed (duh).
You’re done!