Freelander 1 1.8 Idle Air Control Valve buzzes after shut-down: flat battery!

Hi All,

Here's one that no amount of googling has helped much with - I found my battery had completely drained yesterday.

- Yesterday (in the sweltering heat if that matters?) I took the 2000 W-reg Freelander 1.8 for a 30 minute motorway trip and then left it parked up for about 6 hours.
- When I returned to the car the battery was flat (not even any dashboard lights).
- Luckily it was unlocked (not parked in public!!), so I could open the passenger compartment doors and pop the bonnet.
- I poked around the engine-bay looking for something obvious, like a loose battery lead, and realised the Idle Air Control Valve (a stepper motor?) was still merrily buzzing away.
- With nothing to lose I unplugged it and left it a few minutes before plugging it back in. It had stopped buzzing but the battery was still completely flat.
- My brother gave me a jump start and the car sprang to life immediately.
- Drove it six miles to my brother's and turned if off for 30 minutes (Idle Air Control Valve was not buzzing this time).
- I expected to need a jump start again, but this time it started normally.
- Then drove it home (30 minutes on a motorway). Again turned it off and the Idle Air Control Valve was not buzzing.
- This morning, I went to start it up and everything was normal...

So:
- Does the Idle Air Control Valve start doing this when it is starting to fail? Mileage is approaching 80k miles incidentally.
- Could it be a wiring problem (I saw nothing visually wrong)?
- Could simply taking the Idle Air Control Valve off, blasting with carb cleaner and then performing the pedal reset procedure sort this out (I know I'd need a new O-ring).

Thanks in advance..!

Malcolm

Brief update.

1. Tested battery and it seemed fine last night (12.7v) - slow charged it for a few hours anyway as a precaution.
2. Unplugged Idle Air Control Valve electrical connector and blasted the electrical contacts with switch cleaner, allowed to dry and reconnected it.
3. Found a Land Rover tech bulletin mentioning chaffed wiring in the harness leading to the Idle Air Control Valve. Carefully re-inspected wiring and cannot see any damage.
4. Driven a couple of times (yesterday and today) and not seen any recurrence of the continuous buzzing by the Idle Air Control Valve after turning the ignition off.