AEG t61275ac tumble dryer

Hi. we have an AEG tumble dryer model T61275AC Prod no 91609746700 to repair and it has been flashing an error code for months. The customer did not note down what the error code was as she would just switch of machine and start it again. now the dryer is not heating but not showing the error any more. can anyone please post an attachment or reply with how to run the diagnostics on this machine so we can find the last error code shown, and possibly a wiring diagram. thanks

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