Hi Guys,

The nightmare continues with my new purschase, XJ6 2004, 41k miles

Not only do I have no headlights but after carrying out a battery reset to see if that might reset the module I now have had the following messages which clear after stopping the car and leaving for 10 minutes.
Park Brake fault
ABS fault
DSC not available
Air suspension fault

As you do, I have been trawling through internet posts and am finding all sorts of things which may or may not be related including throttle body replacement.
I have renewed another of the earth points behind the headlights so that's 2 out of 3 replaced.

I checked the battery voltage with the car not running and got 12.47v I then started the car and put everything on I could to load up the charge system and it was 14.9v. This leads me to assume the battery is in good condition and functioning properly ?

I removed the wheel liner to check the wiring loom which hides in there and it was all in good condition and completely clean and dry with the drain tube fully intact.

I bought this car to use as my primary means of transport and am beginning to think I have made a bad mistake which is a shame as the car drive superbly well apart from the headlights ( which I need to sort out ASAP) and all of the messages which is really concerning.

I have an OBD II reader but it says there are no codes stored which I do not believe as being correct unless spurious faults do not store if they clear themselves.

Any assistance would be gratefully appreciated, I am loathed to go to the dealers as they charge £142 per hour labour here in Aberdeen but not sure if a normal auto electrician would be able to work on the complex system ( no offence intended to auto electricians)

Thanks
Rob

 

Like I mentioned on your last post...12.47v is low. All these computer networking vehicles are very sensitive to voltage. If the battery is low...12.47v, it will drop considerably when you crank the starter...and that can cause spurious fault messages. I have gotten cascading faults that we're completely cleared by replacing the battery.

14.9 with the engine running sounds like your charging system is good.

 

I Would still suggest a new battery, every time on issues like you are describing. There are multiple threads on electrical gremlins with this car all resolved with a new battery.

 

As has been mentioned - get the battery load tested. How old is the battery? More than likely a new fresh battery will clear these faults.

 

What I would do here is to make doubly certain that all of the earth grounds are not only clean, but securely fastened. You are dealing with relatively low voltages, and the electronics will not work well at all with poor grounds.

 

Get a multimeter / voltmeter that can record minimum and maximum voltages.

Hook it up to the battery, and then start the car so you can see what the voltage drops to when the engine is cranking.

Bet you a pint it's dropping to <10V while cranking which throws up all these random error messages.