So my code reader finally arrived from blackboxsolutions, wasn't so happy about forking out 260 notes but I am quite impressed by the little blue box so far.
After weeks of waiting to find out what the problem is with my Air suspension the fault code is 02032 - Intermittent Cam bus failure. I was thinking a bad connection somewhere. I dried out the moisture in the spare wheel well, checked the compressor plug and socket connections and inspected the cables. No joy there.

Any ideas?

More likely CAN BUS ?

What was the problem again?

Can you clear the fault? If so does it come back immediately or fix the problem and then come back?

No other fault codes or information?

Quote from A BMW forum:

"All cases where a data bus or control unit only fails temporarily (i.e. intermittently) are difficult for diagnosis. In such cases, the entries in the control units' fault memories do not point unambiguously to an intermittent failure of a particular data bus or control unit."

It may be you will have to disconnect parts of the system a bit at a time to track down where the problem lies. If you compressor fires up OK I would tend to think its either a connection problem with the ECU, one of the wheel sensors or one of the other sensors linked in e.g. ABS or Steering Angle. .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
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sorry typo, well spotted, can bus it is.
The fault clears but reappears after a few minutes of driving bringing up the old favourite ABS, HDC and Air suspension inactive. The ABS sensors have been replaced. The steering angle reset and no fault showing. The compressor works fine and the suspension fully functions up and down after the fault is cleared. Very strange and very annoying. The EAS ECU is in the passenger footwell right??

Not sure if it is relevant on the RR's, but on other CAN bus systems I work on, errors can appear if the CAN resistance is not correct. Typically, there will be a terminating resistor at each end of the CAN bus - no idea where these would hide in the RR, but if one of the resistors open circuits, it causes the CAN resistance to become too high, and can introduce faults. Typical CAN systems have a 120 ohm resistor at each end, so the overall resistance would be about 60 ohms. If you can find a plug that has the CAN running through it, unplug it and check the resistance between the 2 CAN lines - this will need to be done with the battery disconnected.

I'll have a hunt around and see if I can find any detail on the CAN topography of the RR's

Cheers - Gav

cheers gav. was not aware of that. if there is one ate each end of the circuit would they not act in series and come to 240ohm for two 120ohm resistors. i suppose measuring the resistance on the can bus is useless with no reference.
I am thinking it will most likely be a faulty sensor but as yet I have no indications on the FCR of this.
One other fault that has come up is the glow coil relay has failed but as this is on the engine ECU I doubt it will have anything to do with it.

In that type of CAN bus, the resistors end up in parallel, so you would get 60 ohms. I've done a bit more research though, and it has a different system than what I am used to. The system as I described it runs in a fixed topography - daisy chain, with a terminating resitor on each end.

The system in the RR is a J1850 protocol CAN - specifically developed for vehicles. It runs a free topography, and has joins, and open ended connections to each part of the system, with no resistors. It is a Pulse Width Modulated (PWM) differential system, which unfortunately I don't know too much about - at the moment, but I have some homework to do by the look of it...

The CAN joins 7 different items - ABS ECU, Transmission ECU, Air Suspention ECU, Steering angle sensor, Engine ECM, Transfer box ECU & the instrument pack.

Without playing around with it, and trying something like CANcapture (pricey - I'll see if work will buy it for me... ) or similar to have a peek at how it all works, I can't really offer too much advise , apart from the basics - check all conections are tight, free from corrosion, with no pushed back pins, etc. Sometimes it pays to start with the basics... If you have a copy of RAVE, it shows what wires the CAN wires are on each plug, and thier locations in the vehicle. I would start at these points. If it is not a wiring issue, then it could be one of the modules sending out an intermittant faulty signal, but narrowing that down would be tedious to say the least...

If I discover anything else, I'll let you know.

Cheers - Gav

thanks gav, all very interesting stuff. The only time I have worked with PWM is on modulated dimming controls of LED lighting systems. Should be WMM - White mans magic