My 1996 Volvo 960 (B6304S engine) recently underwent a head and head gasket replacement at a local workshop, and since getting it back, the cruise control has stopped functioning. I’m trying to figure out if this is related to a vacuum line being incorrectly reconnected during the repair, or perhaps if an electrical component has failed in the process. My hope is that by accessing the diagnostic codes from the cruise control module via the OBD2 port, I can get a clearer direction on how to troubleshoot this issue.
Unfortunately, the repair shop’s code reader was unable to retrieve cruise control module codes through the OBD2 connector. It seems that this particular module might be linked to pin 13, which is typically reserved for manufacturer-specific uses within the OBD2 standard. The standard OBD2 connections on pin 7, which are used for systems like SRS, transmission, ECU, and power seats and operate on the ISO 9141-2 K-line for code reading, are working correctly.
The Volvo Green Books I have access to do not provide a vacuum diagram for models beyond 1995 and are generally lacking in detailed information on cruise control for my specific model year. Older Green Books mention a diagnostic link box in the engine bay for cruise control diagnostics, similar to what’s found in LH 2.4 systems in B23x engines, but this is not present in my 1996 960 with the six-cylinder engine.
Given the rarity of the V90 and 960 wagons in my market – with only 47 imported between 1991 and 1998 – finding a comparable model in a junkyard for reference is practically impossible.
Therefore, I’m reaching out to the community for expertise.
Is it possible to use a simple LED and momentary pushbutton to read the diagnostic codes in the old-school Volvo style on a 1996 model via flashing LED signals? Or am I looking at needing a specialized, and likely hard-to-find, late 20th-century Volvo scan tool, or finding a workshop that possesses one?
Furthermore, does anyone know if a vacuum hose diagram exists, either in a Green Book or available online, specifically for the B6304S engine’s cruise control system? There’s a wealth of information available for the older redblock engines, but resources are scarce for the B6304S, especially for 1996 and newer six-cylinder whiteblock engines. Any guidance would be greatly appreciated.
