We in the 850 family who have 1996 and 1997 model years have it easy. Check Engine light comes on? We just plug in our diagnostic code readers and a magical system called OBD-II tells us what code(s) are causing the CE light. Same with 1998 model year Volvos, like S70, V70 and XC70 models. Then after that, codes expanded from the OBD-II to include Volvo-specific diagnostic codes that OBD-II readers cannot retrieve, although many overlap in meaning.
How To Read Diagnostic Codes
To start, the Ignition key must be in position II, engine not running. Open the hood. Locate the two diagnostic sockets just inboard of the washer fill cap. The “A” connector has a jumper that is stored in the lid of the “A” diagnostic connector. The jumper is used for both diagnostic connectors.