Test Procedure
- If you were not directed here from Lighting chart A-1, then a wrong diagnosis could result. See 1989 SELF-DIAGNOSTICS -- ALLANTE
article in ENGINE PERFORMANCE.
- Visually inspect the cavities and pins of the OSM for obvious connection problems.
- Checks for proper power supply 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.
Courtesy of GENERAL MOTORS CORP.
Courtesy of GENERAL MOTORS CORP.