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Went to start the car today and noticed a loud intermittent clicking noise coming from under the bonnet. Car hasn’t been started for about 3 weeks due to holiday and storm darragh.

Unlocking the car didn’t stop the noise. Lifting the bonnet the noise seems to be coming from just in front of the driver where there is something with an ‘airbag’ sticker on.

Starting the car the ‘ check pedestrian system’ warning came on. Clicking noise became more frequent at about 1 per second. Cleared warning and took it for a run around the block. Ran fine. After about 5 mins the clicking abruptly stopped.

Returned, switched off and on . Ped says warning came on again but no clicking noise.

I have video of noise.

Any ideas?

Thanks Steve

Hi Steve, the "something with an airbag sticker" is the working end of the Pedestrian Safety System - there should be a twin cannister on the passenger side. The Pedestrian Safety System comprises of 2 main elements, aside from the brain part in the computer. There are 2 x cannisters just ahead of the bulkhead in the engine compartment, which you have located. Plus, there are 2 x sensors mounted behind the front bumper, which requires the nose cone to be removed to fully access them.

Either end of the System can be prone to failure and whilst the nose cone removal and sensor replacement can be a competent DIY task, the cannister replacement is certainly a job for someone who knows what they are doing - think small explosive device.

Their function is to trigger a rise of the bonnet in the event of a frontal collision with a pedestrian so as to prevent their head from contacting the more solid components that lie beneath said bonnet.

If you can access a code reader then it may provide insight into which elements of the Pedestrian Safety System are at fault.

Jim Mann

Hi Jim,

Thanks for the explanation. Will have a go with the code reader tomorrow. Still stormy and going dark now!

Steve

I got the code reader on it but it came up with nothing. ( i may not be using it properly!)

However, speaking with someone else they suggested it may be the backup alarms rechargeable battery that has failed. The click noise is similar to what you get from smoke alarms but a lot more frequent. It has happend on XK8's apparently and mine is one of the oldest X150 models.

That backup alarm unit is under the cover near the bonnet airbag i beleive. I took off the cover and (apart from a nest of spiders) I can see a small reservoir with a yellow top and a circular black donut under that. The noise is coming more from under the reservoir there and nothing to do with the airbag.

Unfortunately, nothing looks easily accessible to attempt to change a battery (assuming you can get them, the other person said it was the same as Land Rover systems of the same era). I looked in the PDF I have of the manual of 2006-2009 cars but cant find the rechargeable battery mentioned anywhere.

I've attached some pictures below and open to more suggestions!

Thanks

Steve

On the XK8 there is an 'intelligent sounder' mounted below that area, accessible from the wheel arch by removing the liner. This does fail as it has an internal rechargeable battery that dies over time. However I am not sure it is in the same site on the X150. It may be well be this that is giving you the noise.

The alarm sounder is located below the pedestrian protector actuator. There are several versions of the sounder ranging from £70 to £150 from Jaguar, dependent upon specification, and are not difficult to fit. Mike.

My plan is to take it to Autoclassico after Xmas and let them do it!

Interestingly, I took it out yesterday and as before, clicking stopped after about 5 minutes. The difference is a day later it has not returned. Possibly because we are having a mini warm spell and its about 5 degrees up today? Rechargeable battery holding more charge?

Although in other news the engine light is now on ! Joy.

Steve

Well, it is Christmas and everybody likes extra lights at Christmas! What codes are flagged for the engine check light? Mike.

Well, it is Christmas and everybody likes extra lights at Christmas! What codes are flagged for the engine check light? Mike.

Hi Mike, I emailed a full fault code readout.

As I said in email. When I cleared the codes the engine light went off but was replaced by orange 'engine temperature indication fault' on dash. This persisted after restarting the car.

When i start it again next time I will probably get something else!

Steve

Hi Steve,
I've emailed you with some suggestions. Mike.

The alarm sounder is located below the pedestrian protector actuator. There are several versions of the sounder ranging from £70 to £150 from Jaguar, dependent upon specification, and are not difficult to fit. Mike.

Is it part number C2D47174 from SNG Barratt ? Fits many Jag types. Says 'special order' ? £126 + VAT

https://www.sngbarratt.com/English/#/UK ... e250a1de8f

Thanks Steve

Steve,

It depends on your VIN and whether you've got an inclination sensor.

Always use Jaguar's parts website first to get the correct number, rather than one of the independent suppliers. As you'll see, SNG can't provide it anyway, as it's not in stock at Jaguar. See here:

https://parts.jaguarlandroverclassic.co ... nd/jaguar/

Good luck

Paul

The Garage (Autoclassico) managed to source a part and replace.

They said the old one was sitting in water as a drain hole under the Bonnet Airbag thing had blocked up. They have cleared it all out and put the replacement unit in a plastic bag for good measure.