2002 Defender TD5/10AS Hell

[dr_phibes]

Hi All,

I am having a lot of problems with what I think is an immobiliser issue.

Round One:

Modified ECU to disable immobiliser (by rewriting addresses 1EC to 1F1 of 93C66 EEPROM to 0x00) - per https://www.aulro.com/afvb/electronic-diag...lizer.html (https://www.aulro.com/afvb/electronic-diagnostic-systems/217021-removal-td5-immobilizer.html)
Ran fine for a few hundred K's
Battery failed, replaced with a spare which was getting on, drove fine for a bit more
one day failed to start (cranked but with no ignition)
went through chain of diagnosis and deploying the parts canon (including a brand new battery, starter, fuel pump, relays, injector seals/washers etc)
found that in nanocom injector codes had reset
set codes to correct value
started easily ONCE and ran for several minutes until I turned off...
then failed to restart (cranks, doesn't fire), injector codes had reset
nanocom sometimes shows codes as retained, sometimes not
no faults or codes
No immobiliser indicator on dash, shows as non-robust and immobilised on nanocom


Round Two:

Reinstated 10AS, jumpered wiring so as original
Fitted new ECU
New fuses for ECU and 10AS
Set 10AS to "Australia" setings and then setting as recommended per https://www.aulro.com/afvb/electronic-diagnostic-systems/110127-new-nanocom-evolution-news-27.html#post1445807
Tried to execute 'learning' mode in Nanocom Engine settings... Reports success but when I check status I get "the ECU is immobilized" on the Nanocom.
Still cranks, runs briefly on starter fluid, but doesn't start - convinced injectors aren't firing - will try CSV capture soon
When I changed settings these are saved, which I wouldn't have expected if immobilised?


I haven't tried EKA codes yet as I will need to wire up a door switch to enter it (understand it goes to ground, but need to confirm if it's closed/on when door is open)

Any ideas?!?

Thanks

[dr_phibes]

I left the ignition in position II for 15m and it ran briefly. I reckon this is how it ran the first time (albeit with my hacked ECU)...

I have rigged up a switch to the 10AS Driver's door open/close input - taking it that door closed opens the switch, door open closes the switch to ground...

Enabling the MEMS Failure Indicator in the nanocom causes the immobiliser indicator to flash continuously. I'm assuming that setting won't get in my way.

I noted the original EKA code as reported by the nanocom for the new ECU. It's a painful sequence to enter using the key (9952).

If I set to 1111 using the nanocom, and its stored OK, will that apply - even if the ECU is immobilised? I tried it and it didn't make a difference - although I may have been doing the code entry wrong. I assume it should be OK as the EKA code gets stored at the 10AS.

Whatever I try I can't get the ECU to learn the 10AS code...

UPDATE... confirming if I leave the ignition in position II for 15m, it will then start and run like a champ. And if I restart, nada.

[shack]

The AS10 Is a reasonably unreliable unit.

Did you cut/disconnect the alarm?

[dr_phibes]

The AS10 Is a reasonably unreliable unit.

Did you cut/disconnect the alarm?

I did originally (see round 1) - as my goal was to remove it completely.

I have reconnected it to troubleshoot as I have another ECU where I haven't reprogrammed the 93C66 EEPROM yet to remove the immobiliser.

[shack]

I did originally (see round 1) - as my goal was to remove it completely.

I have reconnected it to troubleshoot as I have another ECU where I haven't reprogrammed the 93C66 EEPROM yet to remove the immobiliser.I figured you probably had but thought it worth asking.

I had concocted a flowchart of events in my head that could have happened to explain your issues, but if you removed the alarm it doesn't work.

[shack]

Are you sure the fuel pump is running?

The relay under the drivers seat for it is notorious for bad contacts.

Have you tried a purge/prime cycle?

[dr_phibes]

Are you sure the fuel pump is running?

The relay under the drivers seat for it is notorious for bad contacts.

Have you tried a purge/prime cycle?

Definitely running. Having been over the fuel system front to back as an original suspect I am confident that it’s fine. And I have a pressure gauge so I can see flow at 4.5 bar. I replaced the pump and main relays with Narva ones (with resistor)

It’s clearly the immobiliser. Every time I leave it for more than 15m she starts. I’m flummoxed by how to get past it without modding my other virginal ECU or repairing the old one as getting nowhere with EKA code. I will try the MEMS application when I get a VAG OBD cable. Apparently it can write to the EEPROM directly.

[shack]

It's unusual that the original de-immobilized ECU now won't run, does it need a functioning BCU to start?

I've not really messed with the defender one, but I'm considering retro fitting a D2 one

[dr_phibes]

It's unusual that the original de-immobilized ECU now won't run, does it need a functioning BCU to start?

I've not really messed with the defender one, but I'm considering retro fitting a D2 one

The one I am using at the moment has the immo enabled. I haven’t touched the EEPROM on that.

I think I butchered the EEPROM or resistor on the one I did modify, so it started behaving erratically.

[shack]

The one I am using at the moment has the immo enabled. I haven’t touched the EEPROM on that.

I think I butchered the EEPROM or resistor on the one I did modify, so it started behaving erratically.Yeah ok, that makes perfect sense.

Been there done that modding stuff as well!

If that's the case it's possible the AS10 has died and that's why it won't sync.

And the original ECU won't work as it's physically damaged.

All adds up now.

So you want to the inmo off on the new one?

What revision ECU is it?

I'll check if you mentioned it earlier..

[dr_phibes]

It's unusual that the original de-immobilized ECU now won't run, does it need a functioning BCU to start?

I've not really messed with the defender one, but I'm considering retro fitting a D2 one


Yeah ok, that makes perfect sense.

Been there done that modding stuff as well!

If that's the case it's possible the AS10 has died and that's why it won't sync.

And the original ECU won't work as it's physically damaged.

All adds up now.

So you want to the inmo off on the new one?

What revision ECU is it?

I'll check if you mentioned it earlier..

They are both NNN000120s. I’m going to ultimately Immo off both. I’m going to try the MEMS kline approach on the newer one. For the duff one will desolder and put a pre programmed chip on. Where I will program with an arduino.

Will ultimately write up a clear how to. As I have only found bitsy posts etc.

[dr_phibes]

So it was immobilising… turns out the ECU won’t fire the injectors if immobilised. I took my new ECU and used the excellent mems3 app to set the immo off. I must have buggered up the EEPROM on my original ECU. Will reprogram and solder in a fresh one…