Technical Check vehicle protection system

[Bikernut]

Got the fault reader today,connected it up and cleared all stored codes.
Strangely enough the engine management light went off.(and hasn`t come back on)
Let it scan again and it came back with a U1700 fault code...Can bus communication error between ECU and body computer.
It also showed a code U1600 immobiliser fault with ignition on but engine not started.(expected)
The fault reader has a live data stream screen that shows stuff like RPM,TPS,ignition advance,Coolant temp,Vehicle speed.All these were working and showing correct data,but still not showing on the dash.
Another curiosity is the power steering...as the fault reader was scanning the different interfaces,as it started to scan the KWP2000 (which i believe is just the protocol used for the CAN network) interface the power steering suddenly started to work.
How could it be that there is obviously communication between the ECU and body computer,as the fault reader is picking up all the sensor information.
Yet its also saying there is a communication fault between them(and the dash as well.)
Unless the OBD2 port has its own communication line?
Artemis..i will have a look into that Multiecuscan,seems very comprehensive

 

[Bikernut]

Well...today is a good day
My usually trusty steed is FIXED .
It was one of the high speed CANBUS connection lines.
In my case it was the green one,it had been gradually chaffing itself to death on the sharp inner sill.The part of the loom that goes from the D4 connector to the computer.
I had been too pre occupied checking the D4 connector itself and the wiring in between the ECU and said connector.
With a stroke of luck i spotted it,in the shadow of the inner sill,still complete,but slightly chaffed.
Pulled all the wiring out that resides there and started picking at the plastic sleeve with my nails and the wire just fell apart,corroded from the inside due to water ingress.
Bit of solder and the car instantly returned to normal.
Unreal how one wire can cause so much trouble :bang:
I checked the new parts i bought..the ECU,computer,clocks,lockset and they are all fine aswell,so i suppose i can sell those on (55k miles)
So now i have the even more difficult task of re assembling half the car.I bet there`s more than just the odd screw left over when ive finished
Thank you to everyone who tried to help,it is very much appreciated