aquascrotum

Still at this...is the ECU tied to the immobiliser? As in do I need the transponder from the original key that matched the car the ECU came from?

As in there may be a legacy error from the previous car it was installed in? How do you clear fault codes if thats the case?

We're running a stock 4EFE with standard ECU, I bought another 4EFE ECU to carry out the rev limiting mod described here When I tried to test the ECU I bought before making the mod (by plugging it into the car), I get an intermittent flash of the engine warning light on the dash and the car refuses to start. Have tried disconnecting the battery before hooking up the new ECU but that doesnt affect anything. The new unit is visually identical to the original, but some of the long model numbers are subtley different - the new ECU is definitely marked as a 4EFE though. Am I missing some procedure to get the car to allow the new ECU or do I have a more fundamental fault?