[bcorcoran]

Hi, I've just joined this forum - grate source of info.

My 2001 Boxster S tiptronic has similar symptoms: some gearbox slip & alternating fault lamp indications.

I'll have to look up the fault code provided from my dealer but their suggested fix was a gearbox overhaul as they claimed the torque converter was worn and residue evident in pan. I took the car to a transmission specialist who had trouble identifying any problems but we agreed to an oil & filter change and some further fault diagnosis. The specialist indicated no one had removed the pan previously and no evidence of residue from torque converter.

The filter & oil change improved the situation for low speed driving but at higher speeds I still get fault lamps, but not always and no slip, no noises, no fluid loss, in fact no change in performance ie can manual shift as normal.

From this forum & others it seems possible causes include wheel speed sensors, transmission plug/sensor or transmission control unit on boot (trunk) wall.

I hope others out there can sort this one!