B2799 ECU to Imobiliser connection issue Help.

[BK09]

Hi Everyone,

I am new to this forum.

We have a 2009 Aygo that has developed a fault  after a heavy rain storm,  basically the enging will crank but not start. Got  a diagnostic scan done & it logged a B2799 error which  indicates that the ECU and Immob are not talking to each other. Done some more digging and managed to find that the following ( I must admit finding any kind of Info on these cars such as plug diagrams is very difficult and frustrating !).

ECU plug Pin           Imob Pin

39    ----->               46

6--------->         12

I removed the ECU plug and it looks dry I then, I checked the connections and found  that only one is good ( ECU pin 6 to Imb 12) and looking at the rats nest of wires I think this is going to be impossable to find the break ( I took the dash out and checked all fuses etc..)

So advice I need is 

1.are these pin outs correct ( the Imob plug has only has a few connections in it and I cant find a diagram ),

2.Can the ECU be reprogrammed so that it ignores the Imobiliser after all this is a 2009 car  so not having an imobiliser isnt going to be an issue, if so how is it done 

I was going to reset the imobiliser and rematch it to the key by linking the two OBD pins, but though if its a cable break then that wont work either. 

( PS I only have 1 key )

Any advise would be greatly appreciated.

Kind Rgds

 

Phil

 

 

 

[flash22]

Well, you found the right place

2 most common causes

1. Earth Point on the front right of the cylinder head - brown wire and a white with black

2. the ACC fuse 15a on the right side of the speedo remove the fuse clean the contacts and use a NEW fuse

 

Lots of info in this thread (3-4 different users)

 

[BK09]

Thanks,

Sorry fopr the delasy in responding but I have been away. 

I have  already checked the ground and it looks ok, I will check the fuse. 

Kind Rgds

 

[BK09]

Quick up date,

 

Tried both the above suggestions with no luck  😞 so am going to have to keep looking. Reasding the other threads I think It may be a connection issue as I cant get a circuit on one of the ECU to Imob links and the other has a high resistance. The car has always suggered from water ingress so it could be a corroded connection somewhere

[flash22]

check the back of the speedo, resistance is that with both ends disconnected?

The Immobilizer requires 3 power sources

as you can see from the other thread water can get into the ecu