Code 07, Serial Data Line Test
WARNING: This page is about a different car, the 1996 Oldsmobile Cutlass Supreme and 1996 Buick Regal. However, it is still accessible from the selected car via links, so may be relevant.
Connect Tech 1 scan tester to Data Link Connector (DLC). Turn ignition on. If communications cannot be established with PCM, see appropriate ENGINE PERFORMANCE article in the ENGINE PERFORMANCE Section. If communications can be established with PCM, check Tan wire at DLC terminal No. 9 for open circuit or poor connection. If circuit is okay, replace A/C-heater control.