Classic Immobiliser fudge up - Saxperience

Crocko2 · 30th October 2018, 19:33

I know the obvious response will be "use the search function"...
But I have to start by saying I have and got so confused by all the conflicting suggestions.
I am in the process of stripping unnecessary wiring, I have EVERYTHING out, pretty much just a shell with an engine at the moment.
In my quest to remove unneeded wiring I found this little black plug above the ignition barrel, the car was running at the time so I unplugged it to see if anything was affected- it wasn't, so I thought great trace the wires back and rip it out. Before I did, I plugged the clocks back in and went to start the car. It was then I realised the immobiliser had kicked in and I now get the orange flashing key symbol and the car just turns over but won't start.
Tried turning key to ignition point and disconnecting the negative battery terminal, reconnected and no change.
I tried turning the key to the ignition point, disconnecting the passenger side immobiliser box, reconnected and again no change.

Any suggestions of what to do now?? How do I know if it's locked the ECU?

andrew_wright · 30th October 2018, 20:05

Quote:

Originally Posted by Crocko2

I know the obvious response will be "use the search function"...
But I have to start by saying I have and got so confused by all the conflicting suggestions.
I am in the process of stripping unnecessary wiring, I have EVERYTHING out, pretty much just a shell with an engine at the moment.
In my quest to remove unneeded wiring I found this little black plug above the ignition barrel, the car was running at the time so I unplugged it to see if anything was affected- it wasn't, so I thought great trace the wires back and rip it out. Before I did, I plugged the clocks back in and went to start the car. It was then I realised the immobiliser had kicked in and I now get the orange flashing key symbol and the car just turns over but won't start.
Tried turning key to ignition point and disconnecting the negative battery terminal, reconnected and no change.
I tried turning the key to the ignition point, disconnecting the passenger side immobiliser box, reconnected and again no change.

Any suggestions of what to do now?? How do I know if it's locked the ECU?

I'm new to this Saxo setup but is the little black box under the dash (glovebox side) still connected? If so the ECU is locked now. Black box on steering column is the pick up point for bit inside key.

Sent from my Nexus 6 using Tapatalk

welshpug · 30th October 2018, 21:17

yeah that was just the aerial, unplugging it wont have affected anything, it'll still lock and with it removed you wont be able to unlock the ecu.

you can fit the ecu and immobiliser box into another car to unlock it without any issues, you'll need to make sure your key chip is read by the aerial, no need to change the ignition switch though.

Crocko2 · 31st October 2018, 05:31

Is it easiest to just buy an unlocked ECU, plug it in, start the car and then whilst running remove the immobiliser box under passenger dash and plug on ignition barrel to avoid this in the future?

Crocko2 · 1st November 2018, 18:10

Hopefully getting an unlocked 3 plug ECU tomorrow.
Step 1 remove old ECU
Step 2 Disconnect immobiliser black box from passenger side behind dash
Step 3 remove transponder from ignition barrel
Step 4 plug in new ECU
Step 5 start car (with crossed fingers!)
Step 6 have a beer whilst smugly listening to the engine running again

Have I got that right???

Furioman · 1st November 2018, 20:48

i am not getting why you bought a new unlocked ecu when you have everything you need to unlock your current one, but never mind. just make sure you have the immobiliser box removed before you plug in the new ecu.

Crocko2 · 2nd November 2018, 05:30

Quote:

Originally Posted by Furioman

i am not getting why you bought a new unlocked ecu when you have everything you need to unlock your current one, but never mind. just make sure you have the immobiliser box removed before you plug in the new ecu.

Still gonna by the unlocked one, as can't hurt to have a spare. But how do I have everything I need? How can I unlock it? I know some people offer an unlocking service via post, but I'm not patient enough to wait for that.
Or is there another way that you know of?

Crocko2 · 2nd November 2018, 13:00

I'm still unsure whether to remove the key transponder before plugging in the new ECU?
Anyone??

Crocko2 · 2nd November 2018, 17:28

Quote:

Originally Posted by Crocko2

I'm still unsure whether to remove the key transponder before plugging in the new ECU?
Anyone??

For anybody wondering this same thing in the future, the transponder connects to the immobiliser under the passenger dash and can therefore be removed at the same time.

My car is now running again, albeit the indicators and heaters aren't working