As is usual with inherited jobs one never quite gets the full story as to the sequence of events, But it now appears that the new ecu was an exchange unit from a company called Lynx and was actually fitted by the owner. This was over 12 months ago and to that end the warranty has expired, But also the warranty seals had been broken before I inherited the job. It also appears that various fault codes appeared almost on a daily basis, This I have cured by renewing all of the under bonnet earth points and cleaning rhe screw on multi connectors on the under bonnet fuse box and also on the `super relay`. With KOEO and KOER this relay switches supply to various ecu controlled components such as EGR, MAP, Intake air temp etc, With key off this relay goes into latching mode, This keeps the supply to the the ECT sensor alive for a few minuets, presumably to switch on the cooling fan due to heat soak. My initial thought was that it may be the relay at fault but when in latching mode the relay also keeps the 5v supply alive to some other sensors such as air intake temp sensor and lambda for a few mins and this supply is present for about 2 mins after switch off. The thought has also crossed my mind that the connector to the relay was full of corrosion and verdigris and may be the cause of the demise of the 5v supply from the ecu to the ECT sensor.
So I suppose the question is this: Do I trust my diagnosis and fit another ECU and relay, or can anyone think of or know of any other possibles, Thanks for reading, Regards, Neil.