Magnum V8-5.7L (2008)
Seat Occupant Classification Module - Air Bag: Description and Operation
Occupant Classification Module
Description
DESCRIPTION
The Occupant Classification Module (OCM) is secured with two screws to a mount on the underside of the passenger side front seat cushion frame near
the outboard front corner. Concealed within a hollow in the center of the molded plastic OCM housing is a microprocessor and the other electronic
circuitry of the module. The module housing is sealed to enclose and protect the internal electronic circuitry. The OCM software is flash programmable.
A non-calibrated OCM is available for service replacement. The OCM and all of the other components of the Occupant Classification System (OCS)
including the passenger front seat, the seat weight sensors, the passenger or driver seat track position sensor and the seat adjusters, cushion, back, frame,
foam, springs, and wiring harness are a factory-calibrated and assembled unit. Any time any one of these components is removed or replaced for any
reason, the OCM must be re-calibrated using a diagnostic scan tool, the Occupant Classification Seat Weight special tool, and the Occupant
Classification System Verification Test. Refer to the appropriate diagnostic procedures.
The OCM cannot be adjusted or repaired and, if damaged or faulty, it must be replaced.
Operation
OPERATION
The microprocessor in the Occupant Classification Module (OCM) (2) contains the Occupant Classification System (OCS) logic circuits. The OCM uses
On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the
Controller Area Network (CAN) data bus. This method of communication is also used for OCS diagnosis and testing through the 16-way data link
connector located on the driver side lower edge of the instrument panel.
The OCM (2) provides voltage to the four seat weight sensors located on the corners of the passenger front seat (1, 3, and 4), and to the seat track
position sensors on the outboard passenger and driver front seat upper seat tracks. The OCM then monitors return inputs from each of the sensors on
dedicated hard wired data communication circuits. The seat weight sensor input allows the OCM to determine whether the passenger side front seat is
occupied and the relative size of the occupant by providing a weight-sensing reference to the load on the seat. The seat track position sensor provides an
