Hi all. My 2006 S-type 4.2L has a parasitic current draw that will deplete the battery in around 4 days. Everything is working and there are no DTC codes in any of the modules ( icar soft 930 ) No lights stay on, including the trunk lights. The last time I had an issue like this. it was on my Audi and was a diode in the Alternator that was leaking. I haven't checked the alternator on the Jag yet other than to check it is charging correctly. It is.
Two things I notice is if I close the car and leave the doors unlocked, after some time the entry alarm will arm with the doors still unlocked and go off when the door is opened, I don't remember it doing that before. Also the "close all" feature only closes the sun roof and not the windows. The "all open" works just fine. These may well not be related to the parasitic current draw, but they may...
Where would you recommend I start ? or should I start pulling fuses/relays. Thanks for the help.

 

Read through this link in the stickies. Its all there. very common topic

https://www.jaguarforums.com/forum/s...-drain-123535/

 

Obviously it's not fine or it wouldn't do it!

There are multiple very detailed posts about how to troubleshoot this in more than one way (all require persistence and logic, some luck helps) which you may like to read to save a lot of time.

Main tool - DVOM. Almost any will probably do but reasonable accuracy helps.

 

Has anyone tested the battery itself? If the battery has less than 12.6 volts across the terminals with the ignition OFF for at least ten minutes, the battery should be replaced.

If there is a parasitic draw, you must check circuit by circuit with the DVOM as JagV8 suggests.

 

Thanks for the link, I pulled rear module F1 (40A) that feeds the PJB and the parasitic current is not there- current draw 29 mA vs 800 mA with F1 installed. It looks like F1 feeds the PJB fuses F6,7,18,19,20,32 and 35. F6,19,32,35 are probably not high the list based on what they feed. So that leaves F7,18 and 20 to try first.
I'll start with those fuses in a couple of days when I have some time to spare. I will report back when I find the offending circuit(s).

 

These may be normal, but am not 100% sure.

The alarm? If you disconnect the battery, the alarm will be armed when reconnected. I've learned the hard way to always have the key fob handy when reconnecting the battery. All seems quiet until you open the door. I suspect in your situation, as the battery slowly runs down, the voltage drops below the threshold to make the alarm think the battery has been disconnected. Open a door, however, and there's still enough juice to make the alarm respond as if the battery had actually been disconnected and then reconnected. I doubt the system is smart enough to know the difference. It's just responding the way it was programmed.

The windows? My '02 only has the global open function. I suspect the lawyers got involved during the design phase and said a global close function isn't the best idea, as you could have a child or pet in the path of the window. I think later cars did have an optional global close feature, but it required dealer-level programming for activation. If so, and this is just a wild guess on my part, it may default to off under certain conditions, such as a battery disconnect (or a reasonable fascimile thereof).

 

Remember, any time you disturb any circuitry (such as pulling a fuse), the car may awake from sleep mode and then you have to wait for it to nod off again. This can be VERY time-consuming.

You can save yourself a lot of time and aggravation by measuring the current flow through each fuse without pulling any of them, using a simple trick. JagV8 has previously suggested this in post #3 of the sticky thread. I gave more details in post #9:


https://www.jaguarforums.com/forum/s...5/#post1891454


The test is as simple as taking a millivolt reading across the two metal dots on each fuse, and then comparing the reading to the chart to get amperage. It is incredibly accurate, too, even for very tiny amounts of current flow.

 

I actually measured the battery voltage when I had finished with the car for the day and it was 12.71 V. I pulled fuse F1, closed up and locked the car for the night. I measured the battery voltage in the morning and it was right at 12.69 V. This indicates that there was very little current draw during the night. With fuse F1 in, the battery would have been at around 12.3 V based on past measurements.
I will pull PJB F7 tonight and see if I get the same results with the battery voltage with F1 installed.This is the lazy mans method !

 

The lazy man's method? Ha? Are you challenging me to a Laze-Off™? Nobody can do less than me. It seems the gauntlet has been thrown down. Challenge accepted!

All seriousness aside, you can save yourself a LOT of work by just taking the amperage measurements at the fuses. You're obviously on the right track, i.e. pulling a certain big fuse which feeds a group of smaller fuses. The downside is you have to wait for the car to go to sleep again and then repeat the process.

If you take an amperage measurement at the same big fuse, without disconnecting it, you will also know if the battery drain is caused by something downstream from there. You'll learn the same thing, but much more quickly. Even better, if the drain does not run through that big fuse, you simply move on to the next big fuse and its respective downstream circuits. If you've got an active battery drain after the car should have gone to sleep, you can quickly find the offending circuit this way in a matter of minutes, versus hours or days when pulling fuses and waiting for the car to go back to sleep each time.

 

Made some progress, the switched system relays 1,2,3,&4 in the rear fuse panel are remaining activated. They are driven by an OR'ed switched ground connection from front and rear electronic modules. It looks like either the front or rear module is sinking the relay control. Next step is to is to pull the front and rear electronic module connector that is connect to the relay coils of the switched system relays to see if its the front or rear electronic module. I may also be an input into either the front or rear module that makes it think the ignition is in the run position. Its not the ignition switch, I removed the power feed ( F3) to the ignition switch, no change. I'll play some more at the weekend. According to the telemetry from the modules there is nothing that seems amiss. All the inputs are what is expected and the outputs to the instrument cluster are correct. All the functions work, so Im suspecting that the circuit in either the front or rear module that provides the ground sink for the system relays.may be the culprit.