Has anyone ever experienced a sudden meltdown of every single electronic system in the XJ6?

My car was not in use for approximately 4 days and when I went out to take it for a spin the battery was almost completely dead and only had enough life in it to open the doors and nothing else.

I tried to jump start it using another car and although I had plenty of power, it just cycled through a number of error messages including:

DSC Not Available.

Gearbox Fault.

ABS Inactive.

AIR Suspension Too Low.

Etc.

I popped the battery out and recharged it which took about 14 hours to get back to a fully charged state, and after putting it back in the same error messages popped up.

I've done quite a bit of research on this site and elsewhere and have looked at a number of possibilities such as checking the condition of earth points near the UK drivers side headlight, which to me looks fine, right through to attempting some integrity checks as per the technical bulletin XJ413-02 which I'm not even sure is relevant to my car based on my car having a higher VIN number.

What caused the battery to run down is beyond me and I can only suspect that the alarm was going off for days due to the recent horrific weather.

Based on another suggesting from a YouTube clip I was looking for some water damage relating to the so called ECU which is near the pollen filter, and although there was no sign of an ECU I noticed that there was a considerable amount of water in the unit that houses the pollen filter, which appeared to get in via a bad rubber seal. Maybe the water leaked into some vital electronic component in the vicinity but I'm not sure.

Appreciate any pointers you could give me on this.

Regards

ED

 

I would take that battery and have it tested, just to rule it out of the equation. Jags do not like batteries on their last legs one bit.

 

The dealer replaced the battery about 6 months ago as the DSC Not Available would pop up occasionally when starting and they suspected that it was the battery.

After charging the battery while out of the car and leaving it out for 2 days it held on to the charge in line with what would be normal for a battery.

I've even tried to jump start it with a Range Rover which has a sizable battery with plenty of voltage output.

Will a charged battery still give out all these error messages even when boosted with jump leads?

 

After purchasing the workshop manual from Jagdocs.com for the purpose for exploring this issue further I was amused to see an official reference outlining their solution to the following technical problem:

-------
Symptom Chart
Difficult to start during hot or cold start
Possible Source(s):

• Piston ring(s) worn, damaged, sticking or worn piston/cylinder.
Action(s) to take:

•INSTALL a new engine.
-------

This possibly the most ridiculous solution to a maintenance problem that I have ever heard Are they for the birds or what?

 

"Based on another suggesting from a YouTube clip I was looking for some water damage relating to the so called ECU which is near the pollen filter, and although there was no sign of an ECU I noticed that there was a considerable amount of water in the unit that houses the pollen filter, which appeared to get in via a bad rubber seal. Maybe the water leaked into some vital electronic component in the vicinity but I'm not sure."

You have identified the problem yourself!

That vital component in the vicinity is the ECU!

Water does enter this area but MUST be allowed to drain out-you must

have a blocked drain and this has water damaged the ECU.

They are available used.

 

Thanks, there were quite a number of leaves in there which must have blocked it up. There's a waterline half way up the pollen filter which indicates that there was a huge amount of water in there at one point.

Would you mind telling me what this ECU thing looks like and where exactly it is located as I can't see any electronic device near the pollen casing and I don't see any reference to it in the 6K+ page workshop manual from jagdocs.

If I get a new unit do I need to get a scan tool unit to reset the errors?

 

I managed to get a second hand ECM for a fraction of the cost of a new one and now all the errors are gone. The only thing is the unit needs to be configured for my car.

Does anyone know what exactly this involves and whether the process can be performed using any of the available diagnostic tools?

 

Take a look at this thread about blocked drainage, I also had the drain holes block a few weeks ago on my X350 but was lucky enough to sort it quickly without the damage to the ECU unlike another poor guy from the UK on here that had a serious expensive bill for the replacement ECU.
Blocked drainage

 

The exact same thing happened to me as per the thread above. In my case it was totally destroyed, but luckily I managed to get a second hand one in the UK. It would be nice if I could program the unit for my car without having to ship the car to a dealer.

 

im having a similar issue that happened right after a car wash, all connections appear dry.

 

Others may disagree but you probably need to get a dealer to program it IMO.

 

If the pollen filter chamber was blocked and your car reported multiple errors, the only way to check this is to pop it out. You can do this without removing the mounting frame by raising the plastic that the ECM fits into using a flat tool to pry the plastic up out of the two indents on the ECM.

If it was blocked for a long time as in my case it could be heavily corroded inside and the car wash was just the tipping point.

Also make sure you disconnect the black cable from the battery first.