Seems a good guide. I can attest to the gearbox sensor problems. I picked up Olga (my 1996 model 960) from the transport company and the WSE lights were flashing as was the one on the dash. As well as the sensor being faulty the contacts on the gearshift can contribute to this problem. I suspect that the low gears were selected manually to load the car on the transporter truck and with the gears not being used very often previously this caused the fault light to occur.
Olga drove fine and changed gears perfectly. I had the fault code reset by a friendly mechanic and it hasn't come on again since.