Hi, me again!

Now I've had the Jaaag a couple of weeks and really getting to know her, a couple of odd niggles remain;

First, I'm getting a fault warning on screen saying 'DSC Fault' most times i turn the key, also my remote locking fob has gone rather intermittent - it usually works fine but often will just do nothing! Tested using spare fob to e same results! Anyone know what this may be?

Secondly there is a slight knocking sound, or more tapping for a few moments sometimes, usually when the car is cold. It could be normal for a car of the age but just wanted to check to put my mind at ease!

Thanks all,
James

 

James,

If you do a search on 'DSC Fault' you'll still be reading at breakfast time. To summarise, it's generally either dirty wheel speed sensors or first signs of a failing battery.

The fobs could have failing batteries (although they often just go from working to dead) or the contacts may be worn / need cleaning.

I don't do noise analysis with out a recording or a drive-by after getting it completely wrong twice recently!

Graham

 

How could I diagnose the failing battery? Wouldn't want to get a new one to find I have the same problem!

And I'll try a new battery in the fobs, seems strange though I believe they were new batteries - Can a low battery problem affect the remote locking?

 

James,
Take the battery to your favourite Kwik-Fit equivalent and they'll test it for free.
These cars are very tetchy about their batteries.
You'll need to have the radio code and retrain the windows when you reconnect.
PLEASE put your car's details in your signature so we can help you better.

 

Most of the Tyre Depots or anywhere that sells batteries can do a battery drop test for you.

A failing or slightly discharged vehicle battery is unlikely to affect the fob. If you recently replaced the batteries in these, intermittent operation is usually caused by dirty or worn microswitches.

Graham

 

I think the Sig be sorted now!

Ok well I've just called my local garage and asked them if they can do a battery test for me and I'm going to pop in this evening. Shall ask him to listen to the knocking sound too.

 

Just thinking to myself, the odd thing is the car always starts fine.... Could that still be battery problems? One would imagine with a low battery the car would have trouble cranking over...?

 

Jaguars generally are sensitive to battery condition but the XK8 raises this to the equivalent of automotive paranoia.

Once the condition drops off, the car will still start perfectly OK but all kinds of mysterious little error messages begin to pop up.

Impossible to put a hard and fast rule on this but after five years the battery is usually past its best.

If you have an OE Jaguar Varta battery fitted, you can check the manufactured date from the WW/YY code stamped into the top of the negative terminal.



This one is 23-12 representing Week 23 of 2012.

Graham

 

This is probably me being paranoid but if the garage are going to do a high rate discharge test on the battery I would insist they disconnect the earth lead at the battery.
Make sure you've got the radio codes though.
I have fried an ECM (Toyota) while messing with the battery I take no risks now.

 

Just quickly popped out to the car park to have a look - it appears that the battery (from what I can tell) is either from 2001 or 2007 week 36 - Can't distinguish between it being a 1 or a 7. But the darn thing looks like it's been in there since the beginning of time. Beast of a battery too isn't it!

 

Yes it is a big b****r!
As Graham reminded another guy - if you do replace it make sure you get a batt with the vent pipe.
The boot is sealed and you really don't want it filling up with a stoichiometric mix of hydrogen + oxygen.
It would do wonders for your 0 -60 time but only once.

 

Beast of a cost too. £103 from Jaguar last month.

Jaguar clear these out from the dealers very regularly and sell them off to specialist aftermarket distributors. Consequently perfectly good new packaged batteries less than six months old turn up on eBay at around half price.

Graham

 

Right then, dropped in on the garage today - Not a Jag specialist but very reliable and he performed a battery drop test, proclaimed that said battery is in a fine condition! So that seems to leave me a bit stumped, I quite expected him to do the test and tell me promptly that it's a knacker!

Oddity the second - I replaced the fob battery and no change, I can lock and unlock the car using the fob provided that I hold the fob right near the rear window. So what could that be? That problem started all of a sudden last Saturday - had been working fine up to last week.

Finally the knocking sound. It sounds to me to be coming from the front..ish of the engine. Had the mechanic have a listen and he said that he can hear it but also said it sounds like theres an air leak somewhere and advised me to take off the engine cover and see if a vacuum pipe has a crack in it - is this likely to happen on this car and could it be a cause of the knocking sound? Its not a bad knock by any means and I'll try to get a sound capture later - also when I got back from the garage I just revved a little and listened and I may be hearing things but it sounded a bit like a faint whistle... sounds odd...

Hope you can all help me out!

Thanks,
James

 

I understand that a slight ticking noise on first startup (engine cold) for just a few seconds is normal. It has to do with oil getting circulated. Mine does it and my tensioners have been replaced.

As far as the FOB sensitivity goes, this is a long shot but your clue of working when close to the rear window made me think.

The FOB works via a radio signal to the vehicle. I believe there is a small antenna to receive FOB signals (looks like a cable that's not hooked up on one end) buried just under the leather cover at the right rear window. I'm assuming that's the side you're talking about as it is your driver's side in the UK.

Take that cover off and see if the antenna is still connected (or even there).

 

I have also read that the variable valve adjustment mechanism can make a valve-like tapping noise until warm. I think my 2005 does that a bit.

 

It's different in a convertible, there's an antenna wire on the hood frame, same side as battery, going to the security and locking module in the boot.
Worth checking it is still attached.

 

Oh goodness my woes get even worse! This morning I got a low coolant warning on my way to work! How on earth does the coolant start getting so low on a supposed 55k miles car!

Words with the dealer may need to be had!

Should this coolant need filling... What do I fill it up with? I've never had to fill coolant on a car before!

 

James,

Coolant Level Sensor is a known issue but NEVER ignore a low coolant warning. The V8 is super sensitive to overheating.

Your 2002 should be using orange extended life coolant. If it's low (correct level is to the base of the filler neck in the Expansion Tank) and you're at work, top up with water rather than drive around until you get coolant. If you want to use an alternative to Jaguar, the spec required is ESD-M97B49-A. If the colour is anything other than orange, post again.

You'll probably want to come back with additional questions about Sensor, Thermostat and Water Pump once the immediate crisis is over.

Graham

 

Thanks Graham,

I've checked the coolant header tank, I can see coolant at the bottom of the tank - I'm guessing that's far too low then?

Also I could swear when I looked under the car I could see what looked like somewhere that water had been leaking down the radiator... but when touched the part that looked wet it seemed to be oil...

 

James,

Correct - that's far too low. It'll take around 0.5ltr to top it up.

Fluid under the car could be coolant, engine oil, transmission fluid or the one that catches most people out the first time they see it - water from the AC drains.

Graham