Hi all, can anyone help with a few questions below?

I have been trying to fix someones Peugeot 406 TD 1.9 tonight, and
need to carry on in a few hours time.
A quick run down of the symptons and fixes.
Car cuts out often, mechaninc advises owner it is the injection pump,
(specifically, fuel cut off solenoid) owner asks me to source and fit
a new one.
I found a match on ebay, and have fitted it. Car now doesn't start
at all. No fuel reaching injectors.

The pump is a late Bosch, with throttle position sensor (for engine
management) and at least one more electrical plug (black 4 pin) I
have never seen on the pumps I am used to (possible immobiliser??)
Car has an ECU, despite being the XUTD9 engine I am used too. Must
be a final incarnation before HDi 2.0 engines?

Questions, if anyone can help with any I would be very grateful.

Inside car when igntion is on, CODE appears in center console. Owner
knows nothing of this, says it happens all the time and doesn't
(didn't) affect starting. Is this a prompt for immob. code?

Opened flap covering number pad, A red light is on. The green light
came on unexpectedly twice, every other time (50) the red came on.
Is red immob. active and is green therefore immob. off? Why did
green come on for no reason?

The owner has never keyed anything in, doesn't know code. Can I
bypass this to see if car will run?

Is the black 4 spade plug that goes into rear of injection pump
(never seen this before on Bosch or Lucas) an immobilser circuit, or
for engine managment?

Could his problems all the way thru be immobilser and not inj pump?
now i have disconnected battery and changed pump maybe I have exposed
the main problem.

Any help at all with 406's and late XUTD 9 engines appreciated.


Finally, if nothing else please can someone scan starting circuit wiring diagram from their manaul for this car?

John UK