Hi,
The battery isn't holding long so I added a ampere logger to the car and double locked it. As you can see it is waking up frequently. Our local jaguar workshop couldn't find out why. Any ideas how to proceed? Is there some usb cable to buy and software to use the PC to track which modules are waking up, and why? Which modules could be waking up?

 

You can find active circuits by looking at the mV drop across the associated fuse(s).

Make sure your battery is holding a really good charge as if it's low it can mean modules do not shut down, which might even be what you see.

 

The modules are eventually at sleep as you can tell by the graph above. But they tend to wake up 5-10 minutes after that. Measuring over fuses would not tell why the module wakes up.
the batter voltage is 12.75V also.

 

It will tell you WHICH ONES wake up. Then you have a chance to tell WHY and WHAT TO DO.

 

Your Jaguar dealer's service department isn't likely going to find the problem. Heck, I'm not sure that I would even trust them for a simple oil change. If it were me, I would pull one fuse out at a time until the abnormal current surge ceases. I'm not saying that it is, but the car's computer itself may end up being the culprit.

 

hi. Sorry dont understand. It's actually goes down to 30mA for 10 minutes. Are you talking about to measure mV over all fuses in that 10 minute period when all modules are sleeping? It's probably the FEM that is waking up because it only has current (before going to sleep 0.9A) going mostly to the passenger compartment fuse box. I had the car in at jaguar and land rover service In Sweden. But they couldn't find the problem. The had a SDD datalogger to the car for weekend but the REM woke up 10 times and the FEM woke up only 3 times for 48 hours. Which doesn't come close to.my logged graph in this thread . Waking up every 45.mins.

 

And regarding the "abnormal current surge ceases"
there are no abnormal current surge. It goes down to 25-30mA as expected. But the problem is that some module is waking up after 5-10 mins after that. Maybe I have to visit another jaguar service dealer that know how to track the modules reset counter correctly to find out which ones really are waking up.

 

Actually I just found out that my Foxwell reader could scan the modules. So I scanned the FEM (called GEM on Foxwell) and will scan again in 10 hours to see the increase in reset count.

 

Not much point measuring the mV when they're all asleep. Measure when they wake up because they won't ALL be awake.

If you can get more data using a scanner, that's worth doing separately (don't measure mV with it in circuit).

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

 

Monitoring the reset count on the FEM and REM will hopefully show you that one is incorrectly waking up. If one increases more than the other you will know which is incorrectly waking up.

It was an issue with the earlier models (launch through till G49XXX range, but it was some time ago I was last involved in this this so the cut off may be wrong).

My car had the REM waking up, and the fault was so bad the counter exceeded the size of the data type. A software re-flash did not resolve it so the REM was replaced. The FEM and REM are essentially the same hardware with different software.

There was a TSB issued about it, but I can't get on TOPIx right now. Hopefully someone will recognise the description and be able to share it?

It might not be that issue though as you have noted that your logs show much more frequent wake ups than your FEM reset counter is recording.

 

Hi. During a period of 11 hours today the FEM counter went from 58484 to 58490. The REM went from 6 to 10. Is the data size of the reset counter 65535 before wrapping?
The FEM is waking up 6 times and the REM 4 times. Im monitoring the rest of the modules reset count until tomorrow .

 

I'm home now so I have downloaded the TSB I was referring to above (attached). Looking at your initial chart, it is repeating about every 40 minutes between waking up and going back to sleep which fits.

Might be worth connecting a battery tender if you have one to ensure the voltage doesn't drop during the monitoring period (keeping it held about 13.5V ish).

It was about ten years ago I had this issue with my XJR so I don't remember clearly, but 16 bits seems logical. I'm not sure it wraps though - it may just overflow into an adjacent bit or the software craps out because I do remember clearly in the IDS live data view my REM reset counter was showing as NaN whereas the FEM reset counter was displaying. When I re-flashed the software the reset counter did not get 'reset'.

(Of course... it could well be something else waking the car up if both your modules are resetting. I only mention the info above because your symptom jogged my memory.)

I know it was mentioned already and you have checked the battery voltage, but it might be worth testing the voltage present at the FEM and REM connectors to make sure they have the voltage expected.

FEM
CR9 12-WAY / BLACK
CR1 26-WAY / BLACK
B+ CR9-06 BATTERY POWER SUPPLY: LOGIC: B+
PG CR1-26 POWER GROUND: GROUND

REM
CR4 20-WAY / BLACK
CR11 26-WAY / NATURAL
B+ CR4-03 BATTERY POWER SUPPLY (LOGIC): B+
PG CR11-11 POWER GROUND: GROUND

 

Thank you for all this. Will monitor the voltage also. Only checked it before the period started and after 11 hour reattached the ctex charger.
isn't it strange that the only module having large counter value is the FEM? And the REM as close to 0 one. Which seems that maybe it resented on battery disconnect or maybe has wrapped around recently and started over from 0

 

Regarding monitoring the voltage at the module connectors. Is there instructions somewhere where to find these modules and how to dismount the door etc. To access FEM module ?

 

Btw If any of the modules wakes up before the other. Will it wake up the other ones aswell? Or are they waking up individually? What the logic/trigger for waking the modules up normally? Is it only through turning the ignition key one step?

 

Hi, I may have found something. I had the ctext charger plugged in this night until this morning. And here's the result of each module reset
Please note the battery voltage is 9.25V only for the DDM module (Driver door module?), is that a 12V module also? Strange that this doesn't show bad voltage." System battery voltage potential under voltage.


DDM Driver Door Module
DSM Driver Seat Module
REM Rear Electronic Module
RSM - Rear Seat Module
GEM/FEM Front Electronic Module

Also attached a pdf with a dump of all live data for the 5 modules above (those are the only ones that are awake/active when turning the ignition key to first step, so could that be only of them that that causes the wakeup during the period?)

 

I can't see why the DDM would have anything less than near battery/charging voltage, so you may have a fault there.

The DDM has two power supplies - 79 (permanent) and 76 (switched), and comms with the FEM over SCP.

Note in this context, a switched supply is one that is activated by either the REM or FEM whenever messages are present on the SCP network, and has no relation to ignition status.

DDM
DD13 26-WAY / NATURAL
PG DD13-08 POWER GROUND: GROUND
B+ DD13-11 BATTERY POWER SUPPLY: LOGIC: B+ (79)
B+ DD13-12 SWITCHED SYSTEM POWER SUPPLY: B+ (76 S)

Tracing each:
79 comes from the passenger junction fuse box via fuse 42/10A which is spliced in the cabin/body harness to 78 (REM and others), 80 (FEM and others) and 81 (the clock).

DD1 22-WAY / BLACK / CABIN HARNESS TO DRIVER DOOR HARNESS CABIN / DRIVER SIDE ‘A’ POST
DD1-9 carries 79 to the door harness.

76 S also comes from the passenger junction fuse box via fuse 28/10A and DD1-6 carries it to the door harness. It is inline spliced to 75 S (climate control module) and 77 S (rear climate control module).

With the car unlocked and awake you should have battery voltage between both DD13-11 and -08, and -12 and -08. If both are good try leaving the vehicle with the DDM unplugged for a few hours and monitor.

The electrical schematics can be downloaded from JagRepair.com - Jaguar Repair Information Resource if you don't already have them.

 

Thank you for all the support.
if I remove the fuse for the DDM could I lock the car then to make it go asleep ever? What should I monitor if the rest of the modules cannot go to sleep due to unlocked?

 

I realise that pulling fuse 42/10A (which is spliced in the cabin/body) also powers FEM, so I cannot pull that fuse to test. So I have to open up the driver side door and find the door module and disconnect that.. D

 

I tried unplugging the DDM ,but the alarm goes off if its unplugged. The only way to get the car into sleep is to have it locked, right?
I'll try to measure the voltage now, or the voltage drop from battery pools to the destination side if there's a cable issue.