B1020 - Occupant Sensor Control Unit
Possible causes
Possible symptoms
B1020 Description
The Occupant Sensor Control Unit suppresses the deployment of passenger air bag when the condition of the passenger seat is empty or child and child-seat. And turns on the cut-off telltale lamp when the condition of the passenger seat is child-seat and child. In the case of malfunction, the blinking of the SRS air bag warning lamp reports the malfunction to the driver and by the on board self-diagnosis system. This Occupant Sensor Control Unit classifies occupant in the passenger seat and detects electrical malfunctions in Occupant Classification System, and transmits malfunction information to air bag control unit.It is integrated into the seat sensor mat and detects the occupants with Occupant Classification System (OCS) control unit that classifies the occupants.

B1020 Information for specific makes
Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service
- Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
- Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
- Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
- Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.