So, 07 XK 4.2 Coupe. TPMS Installed. New Interstate H8 AGM Battery. Full charge placed on it last week, to 13.0V, measured disconnected from car load. NOTE: "Old Jaguar" bluetooth module installed 3 weeks ago; only addon.

Got a "Battery low" code on SDD, after 7 days since charge, about 40-50 miles driven since charge. No ability to attach a CTEK -- in a condo.

Test sequence:

• "System off" Battery disconnected from load, Voltage now 12.55V.
• "System on" (Generator running) Battery Voltage 13.6-13.9 VDC, indicating that charging system doing its job.
• Current test, ammeter in line on neg battery lead, unlock button pressed to switch on "system off" full load: about 9.1A (photo below).
• Current test, all doors closed, lock then superlock to initiate sleep mode: observed 240 milliamp (photo below).
• Note: See Service Manual procedure, below. Should drop to full sleep mode within 15 min. with TPMS installed.
• Wait 45 minutes for drop to full sleep mode and .035 amp (35 mA), as specified in manual . No drop. Constant 240mA draw. Likely parasitic draw.

SO, before I start going through the parasitic draw process:

1. Anyone been through the Parasitic draw analysis?
2. If so, did you find anything specific that caused it? Module? Switch? Figure I'll start with checking what others have experienced.
3. If so, how were you able to force and keep sleep mode so the "voltage drop across a fuse" test procedure is valid?
4. Is there a SDD test procedure that sequentially shuts off modules to isolate draw?

Thanks! I'll post my learnings and conclusions as I go.

Best,

Panthera


Service manual procedure, page 2700:
"Operate the key fob unlock button to disarm the vehicle security system.
· Select ignition mode (without starting the engine) for around 10 seconds.
· Deselect ignition mode, close doors, hood & luggage compartment lid latch.
· Lock vehicle.
· After 15 minutes on vehicles with TPMS installed or 4 minutes on vehicles without [panthera: after 45 min, still drawing around 240mA]
TPMS installed, remove shorting link & note ammeter reading.
· The quiescent current should be
· Replace Shorting link.
· Unlock the vehicle.
· Superlock the vehicle.
· After 15 minutes, on vehicles with TPMS installed, or 4 minutes, on vehicles without
TPMS installed, remove shorting link & note amp"



Unlocked, system activated, engine off

Superlocked, system off waiting for full sleep mode, 45 min wait (should be 15 min to 35mA)

 

So, here's some QC information from various places on JF and other locations:

https://vestest.com/testing-and-trou...v=a284e24d5f46

https://us.autologic.com/news/testin...e-voltage-drop


Basic data on QC issues on several (older) jags.

 

I've tried to use Voltage Drop method many, many times and never had it help me. I fall back to the Amp method on different branches while pulling fuses.

 

Thanks, CJ. I'll try both, if I can figure out how to shut off the alarm and get it to attempt to sleep with the doors open. Any guidance on that? Hope you had a good holiday, Best, Panthera

 

I've not done it on my Jag, but my F150 has a problem sometimes.
As for the doors, it's usually 'latch the door hook with a screwdriver'. Both detents.

 

Yeah, the challenge in either case is to be able to go to sleep mode, not only to meter fuses, but to remove them while remaining in sleep mode. I'll try the door latches.

BMW diagnostic SW had a "set sleep mode" routine. Anyone know of something like that in SDD? Either in my V130, or perhaps a later release? Or in some other diagnostic?

Thanks!

 

Does anyone know how to disable the alarm, so I can work on the car in sleep mode?

I understand the door latches can be set to make the car think they're closed, but not clear how to defeat the movement sensors in the car so the alarm stays quiet.

Thanks!

 

So, I answered my question, at least on my 07 XK coupe. Spent a couple of hours at the shop. Note I can't put a tender on it because I'm in a condo garage, with no power available.

Found I have a very simple and primitive alarm system. Has only perimeter, not volumetric (ultrasonic). So, by opening and double locking the doors and liftgate, and bypassing the hood switch with a jumper, I was able to measure quiescent current in sleep mode. For those that haven't done this, manually locking the perimeter is done by using a screwdriver to click each latch two detents to fully closed. Of course, this is the only way to get to the fuses. Releasing them was by pressing the liftgate button on the remote; and using the manual key to unlock the doors.

Learned a couple of things:

• With an ammeter (10 or 20 Amp capacity) in line with the negative battery post, you can watch the car go to sleep. Mine dropped in clear increments from about 9A to .250 A (250 mA) in 3 minutes, then remained there well past the 15 minutes specified in the manual (EDIT: Other writeups, and my testing seems to mark the X150 sleep mode to 3 minutes. The XK Service Manual seems to be wrong in this matter) to get to the 30-50mA sleep value. So, I had a small drain of approximately 200-220 milliamps. The sleep process steps were very consistent in time and value.
• From this I can calculate the drain in 24 hours: Figuring a 1/4 Amp per hour, it should drain about 6 amps per day, or 42AH per week.. This is compared to the normal drain of 720 mA per day of quiescent current, or 5 AH per week. All of this means the parasitic drain will take my battery to 50% SOC in 10-14 days or so. So, it's enough that it matters. It is constant, not intermittent. This is at 70-80 F (Florida). Another thing: my car runs differently at full State of Charge (12.75 - 13.0V) than it does at 60-70% (12.15 - 12.30V). At the lower level, I can hear a regular audio interrupt every 15 seconds, that vanishes at near full SoC.
• For convenience, I figured I'd start with the metering fuse voltage drop method. It didn't work for me, because I couldn't test the small fuses (5-10 amp) accurately. Larger values had clear test points -- smaller ones did not. So, I could measure about 2/3 of the fuses with 0 V voltage drops, but 1/3 I couldn't trust what I read.

My next test is to mount the ammeter where I can see it and begin to pull fuses -- starting with the smaller ones.

Plan B is to see if I can find a solar panel that can generate 200+ mA in indirect light. I'm parked in a garage about 20 Ft from a large west facing opening. I'd rather chase down the problem, though.

Cheers, Panthera

PS: The Manual and the doc below seem to disagree on sleep more timing. Please see attached.

 

Nice write-up so far!

 

Thanks!

A couple of more learnings, probably obvious to those with electrical/electronic backgrounds. I was pleased to see that the current draw was 9A, since my meter has a 10A fuse in it. Unfortunately, it's board mounted, so replacing it would be a soldering job after I order new ones from Amazon...so job would end for the day.

The point is you need to make sure you shut everything off that you can, including entertainment and anything else, to keep below the limit. Of course, the car is not running, and don't switch on lights while the meter is in line or you'll pop the fuse or smoke the meter. And hitting the starter for 100+A would be cool to see, for a second or two.

Second, you need to have a second meter that can read down to .1 millivolt (1/10,000 of a volt) to use the fuse voltage vs. drop tables. But this V drop amount varies by fuse size and amp draw (see the tables from a previous post).. Realistically, a 200 mA draw (my range) across a 30A minifuse would be .4 millivolts drop. Same draw across a 5A minifuse would read 3.9 millivolts. So, you could possibly do without that extra digit on your meter, but it's a good idea to have.

One final item. If you're going to take a shot a the voltage drop method, watch your ammeter for at least a few minutes to make sure the draw is consistent. An intermittent drop can drive you nuts as you pass by that damaged circuit when the draw has momentarily vanished.

Probably be a couple of days before I take my next shot at it.

BTW: If anyone can point me to the 07 X150 fuse charts, I'd really appreciate it. I've got the electricals, but no fuse charts therein.

In the meantime, have a good new years!

Best, Panthera

 

Well done @panthera999 .
Incidentally, my car has sat unlocked for 6 months, last spring. It was not on a battery maintainer. Though I haven’t gone into the investigative procedure you have, I can only surmise that the draw is lower when not locked as she started right up.

 

I've had luck with the fuse pulling method. You will wake different modules up when pulling some fuses. I would just re-install fuse and let it go "to sleep" and move on to next. Its time consuming but you will most likey find the drain. I had one that the Body Control Module was the culprit after checking/pulling all fuses. Good luck!

 

Here you go (from the Owner's Manual for RHD XKs)

 

Ha! So it's it's in the owners manual.... I should RTFM....

Time for a dope slap.... Thanks, Bill!

 

As Stuart S often says, the best way to thank me is to hit the button.

 

Well, it's going to be a few days before I can return to the parasitic drain diagnosis, so I'm distracting myself into building a cheap clean 12 VDC power supply for later programming.

The hack is built on the platform of a HP rack server power supply. I ordered one for $25, including shipping, rated at 1200 watts (100 amps at 12 VDC, but I'll mod it to 14 VDC for 85 amps). It's basic "cookbook electronics", but it can still kill you, so if you decide to do it have at least the basic knowledge of soldering, capacitor discharge after powering off and a few others things that will keep you alive. Been meaning to do this for awhile.

This guy does a great job of explaining how to do it so he can program his BMW. All the info is there, with a couple of comments. He a German engineer, so he overengineers the heck out of it, but what he's choosing to do is correct. I won't do all the heavy duty switch stuff, nor the parallel supplies, or the attached meters. But between a $25 supply, half a $10 jumper cable and a few careful uses of insulating material, I'll get a nice stable source while programming. Note that I'd switch it on and let it stabilize before hooking it to the battery.

Note also how he tests the unit on his car before programming with it. Also, that he has his meter connected wrong at first, so it shows a much larger current demand on the test BMW than actually exists. The correct number is towards the end of the vid at around 30 A or so.

 

Pulling fuses is not recommended, you never know what will wake up when you push the fuse back in.
The way I use is to get a clamp on ammeter. First clamp on the Batt neg cable, record your draw. Then go to the big fuses in the trunk
and clamp one wire, then the other to see which has the draw. Then you can follow the wiring diagram towards each fuse box to pick the one that
has the draw. From the fuse box, you pick individual circuit wires to continue your search.
Don't forget to check the starter and alternator cable for draw.

 

So, I received the HP power supply. Tests fine at a clean 12 VDC. But, 12VDC isn't enough when using it in practice. Ordering a couple of resistors to re-rate it to about 14 VDC, since that's about what Jag's specs call for. Will post results when I connect the resistors. Probably a week to get them.

Couple of things. There are multiple alternate 12V rack type power supplies out there. Great power for cheap, BUT you need to make absolutely sure you're modifying the exact one that's called for in whichever vid you're using.

Mine is the exact one called for in the video above ($25 plus $10 shipping), and to re-rate it to 14V will require a couple of resistors placed in the right location.

Total cost including half a set of 4 or 6 Gauge Jumper cables will be about $50.

I'll take pics when finished.

Jags are fun....

 

OK, two updates on the above. Reminder: this is a '07 XK Base coupe, 80K miles.

The Power Supply: This was a challenge. Not the PS (it was fine) but trying to modify it to 14V was impossible. I've been soldering for many years, and the components were just too damn small to work with. After carefully getting the two resistors on the too-damn-small board, I loosened a surface mount resistor with no way to reinstall it. No idea what it did, and no way to find out. Might have no effect, or might fail under load and spike the voltage in the Jag. So, I tossed the unit ($25 is not worth the risk). I'll get a new one and go with the stock 12.5 V. I'll advise the result, but no hurry.

The Parasitic Draw: Remember, I was pulling 230-240 mA after shutdown, even with a double lock, compared to the spec of 35mA or so. I couldn't find anything useful with the voltage drop method. But what I did find was by accident. When I tested all the fuse voltage drops, I made sure to firmly tap all the relays with a wrench. My electronic training told me that old relays stick. Mattered? Don't know. One of those "maybe it'll help" things.

So, testing it again, I shut off the climate control and audio system before the shutdown.. Then I shut down the car with two presses on the remote's close button. Result: it shut down in three minutes to 14mA, compared to the 230mA previously. Since then, I always shut off Audio; fully shut off Climate on the appropriate screen; and double lock the car. No further problems with parasitic current draw.

The only thing I'm sure of is that Audio and Climate off, plus a double lock, works. No idea if the relay tapping mattered.

(BTW, anyone have a map of the relays in the car? Most relays fail, eventually, and I have no way to find where the relays in the electric diagram are actually located.)

On to the next thing. But the list is getting pretty short.

Regards, Panthera