Alarm/ Immobiliser Guide MGTF LE500

Hi, This is a wiring diagram for security system on later MG TF with super locking and how door locks are wired if it helps.

 

Cheers,  Mark

wow...thank you both, PScan and markvrs... 

I've included a pic of my SAIC Pektron input plugs. There's 4 m/plugs which tallies with markvrs pic

Sooo...I use the markvrs diag to find which m/plug has that colour combination of wires (2 lilacs and a brown), remove it and use + probe on each one of those pins in the m/plug (the darker lilac and the brown) one at a time, - probe to an earth, and see if twisting the driver door key/switch changes the voltage? (are the wire colours actually the same as on the  diagram?) 

 

Okay, assuming the voltages change, we'll have affirmation that the door switch is registering and that the EKA number signal gets to the scu...

Arrgh...what if they don't change - and (aargh) what to do next if they do change?

Hi ,

Yes colours are same as diagram. Plus code is written next to wire, eg B, 2.0D is Black Size 2mm wire diameter .  PR, 0.5D is Purple/Red 0.5mm diameter.

C1449-2 is connector 1449 and pin 2.

Cheers
 

Brill...thanks...and is my test method okay?
(or will there be wisps of smoke?)

My understanding is that the voltage on the wire will be pulled high (to 12 or 5v) by the ECU. When the key is turned it shorts the wire to chassis. If you unplug it from the ECU then the "pulled high by the ECU" element is gone and so you won't actually see any voltage change.
If you can find a way to measure the voltage with loom still plugged into the Pektron ECU then that would be better. 

Erm, sorry I meant unplug it from the scu (if that's the same as the 'bcu' on yours and Mark's pics) or is your bcu the ecu?  

(Isn't it the Pektron scu that allocates EKA?)

SCU, ECU, BCU all means the same thing.

One difference I noticed is that pin C0661-8 is there on the TF but not on the 25.
On the 25 it's on a different page and is connected to the door switch (that makes the interior light come on? ).
Is it the door switch integrated into the central locking motor on the TF?

Yes, curious...especially the fact that EKA doesn't get a mention in the SAIC user manual, yet the Pektron scu gives it up to Pscan interrogation.

I'm getting the feeling that we'll never solve the mystery of the missing SAIC EKA. Other than markvrs no other PScan/SAIC owners have engaged in the thread to confirm or deny their own EKA, I'm afraid