Probable cause - Probable fix - Isolater/immobiliser 10AS problem 2007+

**Rick Fischer** · 30th August 2018, 06:44 PM

Too important methinks to sit perhaps unviewed at end of my original Thread. So new thread. :0)

Probable cause - Probable fix - Isolater 10AS problem

Following a total lack of interest from JLRA and ther previous unhelpful responses, over a year since recurrence I think I have the solution - is fingers crossed. Easy and obvious once aware of what has probably happened, just a matter of eventually joining the dots.

Pennies dropping required a few things to not happen.

Go look at your rear door locking mechanism wiring. There is not a lot of copper, what there is is fairly large dia strands. What happens is that due to the change of angles at the hinge line the wire fractures inside the insulation inside the rubber hinge boot.

In my case following a faiure of one of the door lock mechs, I installed a bypass to obviate removing the whole harness; worked fine for a while but failed again later because I had used similar cable in the bypass. I replaced that whole harness from between the plugs with large dia multi strand speaker cable plug to plug as close up as I could solder.

Somewhere in there with the "genuine" failed/failing door latch wiring and spurious locked/unlocked signals I had my first total faiure of the 10AS system. I still hadn't connected the two events.

Long story short, twelve months later happened again as top of this thread, (a no go) and that describes what sort of happened. A while later I had total failure of the other rear door latch mech. Same problem, work hardened copper wire in the door hinge bend. Again replaced that with heavy multi strand speaker wire. No more rear door latch problems!

Now over twelve monhs since last 10AS isolator/alarm problem - touch wood!....................and no door latch problems...............................and all the other bits working as advertised.

Conclusion: (tentative)

Broken strands inside the rear doors harnesses inside the insulation, giving an intermittent open circuit, and sending incorrect/confusing signals to the 10AS Isolater which in turn causes/caused the ECU to not recognise any Fob signals.

Somethng for the Good Oil??

Cheers

Rick F

**DazzaTD5** · 2nd September 2018, 11:01 AM

Its a reasonable thought and path to go down, I'm not knocking the idea on the head, but....

*Your sample size of one, especially on a Land Rover, isnt really enough. Bring up a age old fault on a Land Rover and you will get a 100 different methods that worked for each owner.
*The broken wire in the rear side door harness is a common enough fault on the Defender TDCi (puma) 2007 on wards. I have changed out dozens of them but none developed a 10AS fault.
*I replace them with a genuine new harness and they havent broken like the original ones (well not yet).

*The 10AS failure or the commonality of it occurring is something that has come about with the Defender 2007 model onwards, the Defender TD5 rarely had this issue. This also goes for the broken harness.
*At least the 10AS can be repaired, its the two immobiliser units after the 10AS that are of a real concern.

BUT... the more AULRO members that work on the issue, then sooner or later someone will come up with a good working solution for the Defender 2007 onwards immobiliser issues.

**weeds** · 2nd September 2018, 12:04 PM

Can the 10AS be disabled/programmer out of the ECU like the TD5.....?

**Rick Fischer** · 2nd September 2018, 02:05 PM

in my original post now at the end of quite a few pages did say "touch wood"

**HUE166** · 10th February 2023, 12:37 PM

Originally Posted by DazzaTD5

Its a reasonable thought and path to go down, I'm not knocking the idea on the head, but....

*Your sample size of one, especially on a Land Rover, isnt really enough. Bring up a age old fault on a Land Rover and you will get a 100 different methods that worked for each owner.
*The broken wire in the rear side door harness is a common enough fault on the Defender TDCi (puma) 2007 on wards. I have changed out dozens of them but none developed a 10AS fault.
*I replace them with a genuine new harness and they havent broken like the original ones (well not yet).

*The 10AS failure or the commonality of it occurring is something that has come about with the Defender 2007 model onwards, the Defender TD5 rarely had this issue. This also goes for the broken harness.
*At least the 10AS can be repaired, its the two immobiliser units after the 10AS that are of a real concern.

BUT... the more AULRO members that work on the issue, then sooner or later someone will come up with a good working solution for the Defender 2007 onwards immobiliser issues.

Where do your source the new harness to change out?

For the longest time my rear passenger door (2011 110 DCPU) hasn't locked when using the fob. I have been locking it manually before locking all of the others with the fob.

Recently, the fob seems to be totally ineffective (with a brand new battery in both fobs) and the red (alarm light) on the dash is on (solid red). (We only lock when we take the ute into town)

If you hop in and try to start the engine there is no action from the starter and the horn gives two short blasts.

Am I experiencing the same problem as is being described above?

**DazzaTD5** · 11th February 2023, 12:29 PM

Originally Posted by weeds

Can the 10AS be disabled/programmer out of the ECU like the TD5.....?

No, but you can't disable it on a TD5 either.
the 10as is part of the vehicle wiring and there is a signal from ecu to imobiliser back and forth that allows the Defender to start.
on the Defender TDCi 2.4 with a 10as the signal goes via the IP cluster (the instrument panel) but isnt used, its a signal in signal out.

all you are doing is turning off the handshake functionality of the 10as between the PLIP and itself.

**DazzaTD5** · 11th February 2023, 12:33 PM

Originally Posted by HUE166

Where do your source the new harness to change out?

For the longest time my rear passenger door (2011 110 DCPU) hasn't locked when using the fob. I have been locking it manually before locking all of the others with the fob.

Recently, the fob seems to be totally ineffective (with a brand new battery in both fobs) and the red (alarm light) on the dash is on (solid red). (We only lock when we take the ute into town)

If you hop in and try to start the engine there is no action from the starter and the horn gives two short blasts.

Am I experiencing the same problem as is being described above?

when i say harness I mean the door harness from the lock solenoid to the B pillar plug
if the red light on the dash is solid it mean the battery in the PLIP is flat, BUT the fact it wont start means its lost its sync with the 10as

no i would suggest your issue is the more common and random lost sync, it more often happens when the main starter battery AND the battery on the PLIP goes flat.
someone with a GAP tool can do it before you have made a cup of tea

Thread: Probable cause - Probable fix - Isolater/immobiliser 10AS problem 2007+

Thread Tools

Probable cause - Probable fix - Isolater/immobiliser 10AS problem 2007+

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions