i have spent lots of time trying to find out why the gearbox light comes on and off
most the time it is the cc system trying to find a gear or just learning when to bite with the clutch the whole system is constely learning, the light may just off come on because the f1 oil level got low.
has your car had a clutch or any thing tampered with the cc system
if you have any trouble with the gear box or clutch please ask me any thing
i always like to help
Make sure you manually return your reverse lever to its resting position after engaging reverse. Sometimes it does not spring back all the way, and though the car goes into forward with no problem, failure of the lever to return completely can throw a code.