2009 xkr 5.0

[chrisarnold67721]

I wonder if anyone can help me? My 2009 xkr 5.0 has a buzzing sound under the bonnet. It is at the back end of the engine on the top, just a few inches from the windscreen. When I turn off the engine sometimes 10 mins or sometimes an hour or 2 the buzzing starts. If I go to open a door or press the black button on the door handle, or open the boot the sound stops, and then will start again later. Has anybody any ideas.

[JimboV8]

That could be the first signs of a failing back up alarm sounder. I say could be as trying to diagnose a noise very the written word is just pure guesswork.

[jh8522]

I have the same issue (2009 XK 5.0 Portfolio), any advice will be greatly appreciated. I have recorded the sound: https://www.youtube.com/shorts/8Jqd5agTcBo.

A short while after I lock the car with the keyfob (typically 3 minutes) an electronic noise starts sounding (not the main car alarm; audio clips attached to this email) and persists for a period of time and then ceases (it seems to vary from around 20 minutes to many hours). The noise appears to be coming from near the fusebox in the engine bay. Unlocking the car temporarily silences the noise, but it comes back again when relocked (and sometimes when left unlocked) as before.

It appears to be instigated by the locking/unlocking of the car, but there have been two instances of it starting on its own - the first one the hottest day of the year a few weeks ago, and the second yesterday (another very hot day). On the first occasion something seems to have also triggered the alarm on the CTEC trickle charger that was attached directly to the battery terminals.

[mike020150]

From the limited information available in this post, I would attempt to narrow down the possible culprits by first checking the cooling fan for the engine ECU. I don't know how long it's programmed to run after switching off but, if it's running for a very long time, suspicion must fall on its temperature sensor. Jaguar only lists a complete fan unit (~ £420). I suggest it's very likely any temperature sensor is part of the fan unit, unless the fan is using an existing input from elsewhere, e.g. the engine air temperature sensor which would be less accurate for the temperature of the ECU and hence less likely. Mike.

[MarkX]

One other possibility - there is a fan that runs on the audio amplifier. I'm guessing it runs until a temperature sensor tells it to turn off. When I first got the car I found it a little concerning and took it back to the dealer as it did appear to be a little noisy.