gears tripping

[Mhk]

I have a 07 c4gp semi automatic
gear trips into manual from automatic when I come to a stop and the goes only to 3 gear
switch off and restart goes fine but as soon as I slow down or stop trips back into manual.
went to local mech put it in computer comes up with no gearbox faults.
any advice or solution

[GiveMeABreak]

Yes - get a proper diagnostic by somebody who has the correct equipment to diagnose the EGS gearbox ECU. There are hundreds of fault codes with these systems and there will 99% of the time be a fault code registered when this happens. Without the correct code it will be very difficult to correctly diagnose as these systems are plagued when they go wrong and can be expensive to resolve if parts are required - so very important to get a proper diagnosis in the first place.

You really need to have an Actia with Diagbox to read the ECUs correctly - as not all third party scanners can interrogate the manufacturer-specific ECUs and codes.