The ecu doesn't support ordinary diagnostic tools. You need to get an mbe can link and the easimap program on a laptop, or find someone who has it as the link is expensive for a one off job, and see what the readings are when the fan comes on. This is for a uk cable throttle car. Eu cars, and I think the 1600 on the jenvey throttle body carb replicas, are on a different system that does support diagnostic tools.