Peter,

it is called "Lamda Sond" not Lambda Sound...Lamda Sond is the sensor that is find in the 3-way catalytic converter of these cars; it was a first by Volvo and it was first implemented in 1976 (if I remember correctly). Its main function is that it eliminates about 95% of the regulated emmissions (HCs, NO and CO). Volvo has a long and admirable record in building environmentally sound and responsible cars (i.e., as of 1990 all Volvos are asbestos-free, as of 1991 all paints utilized at the factory are fre of toxic solvents since they switched to water-based paints, etc.)

I do not know the codes, perhaps a tech can answer that.

Yannis