WARNING: This page is about a different car, the 1990 Oldsmobile Toronado, 1989 Oldsmobile Toronado, and 1988 Oldsmobile Toronado. However, it is still accessible from the selected car via links, so may be relevant.
Codes 11 and 12 indicates problem with EBCM. In most cases, either code indicates replacement of EBCM. Ensure ground circuit is okay. False code can be set due to external electromagnetic disturbances.