I find some great files that describes how to diagnose the fault codes on Volvo 240, 740, 940 and 960. This instructions and files are written in English.
The Volvo 240, 740, 760, 780, 940 and 960 series from 1989, non-turbo engines only and 1990 to 1995 for both turbo and non-turbo engines were fitted with an On-Board Diagnostic unit in the engine compartment. It is mounted behind the left strut assembly and can be used to check for Diagnostic Trouble Codes (DTC), more commonly known as fault codes, in both fuel injection and ignition systems.
The first attachment has instructions for using the unit on the 200, 700 and 940 with a list of codes, which may not apply to all models/years. It also contains some further checks to be carried out when certain codes are detected.
DO NOT disconnect the battery cable until you have checked that the codes have been deleted. If the flash code 1-1-1 is received the codes have been deleted. If the flash code 1-1-1 is not received then disconnect the battery cable to erase the codes. Disconnecting the battery cable will force the computer into a relearn mode which can produce some driveability problems until it has gone through this process.
upp på den V70 Fas2 som vi lagt timmar på att felsöka. Del 1 finns här 
