[david simpson]

Hi Justin

When my 260 went through a similar process with the same P0443 fault code a testbook T4 was used initially in the ecu replacement / renewal menu - this returned the same (option not available ) T4 error message as you seem to have experienced.

The immobiliser maintenance system T4 menu options were then selected and synchronise immobilisation was selected (with the new engine ecu in place) and T4 gave a writing data type of message and all was well.

The car started and has run without any fault code appearing, ( a couple of 40 mile runs ).
The ecu came from brown and gammons just before Christmas it was specific to the 260, new old stock.

The 75 v8 auto also needs a specific differently configured ecu.

The vid block, as I understand it is a partioned piece of the engine ecu memory that is dedicated to the Vehicle's Identity Data.

The VID section would have model, fuel, engine size, gearbox type, wheel size etc data stored to allow the ecu to cater for the specifics of the vehicle. For a new virginised ecu specific to the 75 v8 auto the specifics should all be present but the car's actual Vehicle Identity Number would be absent as it is specific to each individual car.

A missing VIN number and maybe other details, that T4 fails to write to the VID block of the new ecu / Gateway could present a VID block fault code. The gateway ecu seems to form a data bridge between the Ford engine control unit the MG Rover side of the car's electronic systems and T4.

So for your 75 v8 auto car to present a VID block data fault code, (with the correct ECU present), perhaps T4 hasn't written the vin / other car specifics into the vid block / Gateway controller. So this may need revisiting with T4 with the usual precautions around having a well charged car battery and ideally a trickle charger in place to compensate for the current demand being drawn during the process if the engine isn't running with the ignition is on. As you say - the 260 and 75 V8 have an on / off relationship with T4.

Or is it possible that the ECU you have isn't the appropriate 75 V8 unit meaning that the VID block would contain data from a different vehicle and present a VID block fault code. When my ecu arrived it had a part number and sticker associated with the MGZT260 and a manufacture date in 2005.

Regarding the other P0400 type pending codes, they sound to be associated with the evap emissions system that has already been extensively checked over.

It may be prudent just to check the evap valve solenoid electrical connection is still secure and that the evap valve diaphragm lifts from it's seating opening the suction port allowing engine vacuum to evacuate the fuel tank / charcoal canister fumes via the purge tube when the control solenoid receives the actuation signal from the ecu.

The valve function test can be achieved by disconnecting the white fuel tank connector and listening / feeling for air suction at the open evap valve port. With my 260, the evap system runs within about 10 mins of the car being started from cold and left to idle. The evap valve is normally closed so without an ecu provided electrical earth signal the open valve port where the white socket connects would have no airflow.

There is no fuel tank pressure sensor or evap purge flow sensor on the 260 so the only evap system component that is directly monitored is the evap purge valve electrical circuit. There has been some speculation that the change in rpm sensed by the crank sensor and / or a change in air fuel ratio sensed by the O2 sensors is used within the engine ecu to monitor evap system performance.

Hope this ramble helps
Best of luck

Dave S.