DTC L205: OSM No. 5 Communications Problem
WARNING: This page is about a different car, the 1988 Cadillac Allante and 1987 Cadillac Allante. However, it is still accessible from the selected car via links, so may be relevant.
NOTE:
When all diagnosis and repairs are completed, clear codes and verify operation.
Code L205 indicates that the BCM has been unable to correctly communicate information to OSM No. 5. This fault could affect the operation of the footwell courtesy lamps, door courtesy lamps, stowage courtesy lamps and the map lamps.
NOTE:
The following numbered steps refer to circled numbers on diagnostic chart. See Fig 1. For circuit identification, see Fig 2.
- If you were not directed here from Lighting Chart A-1, a wrong diagnosis could result if not performed first. See LIGHTING CHART A-1 in SELF-DIAGNOSTICS article in ENGINE PERFORMANCE.
- Visually inspect the cavities and pins of the OSM for obvious connection problems.
- Checks for power to the OSM.
- Checks for proper ground to the OSM.
- Checks for proper OSM address identification.
- Hazard flashers will increase data line activity. Typical voltages will be between zero and 5 volts and will constantly be changing. This will help identify whether the OSM or the data line is the problem.