The ECU light came on in my 2002 156 JTS Selespeed after going over a speed hump. Code showed speed sensor error and was reset by my local Alfa specialist. Came on again after 500 miles or so, including two episodes of the flashing light and continued warning bleep (both of which were resolved by switching off, waiting and restarting). Reset by Alfa specialist again, who found "no codes". Almost immediately the light reilluminated. Car still ran OK, with only a slight misfire under load. I've booked the car back in for another check tomorrow, but yesterday morning the light extinguished itself, after a couple of hours parked in the sun.
Has anyone had a similar experience? Was there an easy fix? Is the car pining for a Milanese climate?
Will the ECU have retained any code relating to the last episode, or is it pointless to take it in again tomorrow?