THEORY OF OPERATION
The OCM monitors the bladder fluid pressure to determine the occupied or empty state of the passenger seat and verify the operational status of the bladder. To determine the operational status of the bladder the OCM monitors the bladder fluid pressure and temperature. The bladder fluid pressure and temperature are analog measurements and converted to digital counts.
The Occupant Classification Module (OCM), seat cushion and bladder are calibrated as one unit in the assembly plant. The OCM will automatically re-calibrate the assembly from time to time to retain the calibrated relationship between the seat, bladder and module as the seat and bladder change due to age and wear. The re-zero Occupant Classification Module Test uses a scan tool process called the Occupant Classification System Verification Test to force the OCM to re-calibrate or re-zero. To ensure the up to date calibration and functional performance the scan tool Occupant Classification System Verification Test is performed during and after servicing the system.
When powered, the Occupant Classification Module (OCM) on board diagnostics monitors the CAN Bus messages from the Body Control Module (BCM) to determine the minimum and maximum system voltage.
When powered, the Occupant Classification Module (OCM) on board diagnostics monitors the CAN Bus messages from the Body Control Module (BCM) to determine the minimum and maximum system voltage.
During power-up, the Occupant Classification Module (OCM) monitors the CAN bus for the VIN message. The bus message must match the OCM vehicle line configuration stored in the OCM.