U0154 indicates the vehicle’s primary communication network has lost data contact with the Occupant Classification System (OCS) module, which detects passenger weight to enable or disable the passenger airbag. The module is typically mounted beneath the front passenger seat and communicates over the CAN bus. When this code sets, the airbag system cannot verify occupant status, usually triggering a warning lamp and disabling the passenger airbag.
The occupant classification module itself suffers internal electronic failure, preventing it from transmitting data on the CAN bus despite receiving correct power and ground.
Harnesses and yellow connectors routed beneath the seat are subject to flexing, moisture intrusion, and physical damage from cleaning or objects, causing open circuits or high resistance.
The twisted-pair CAN high and CAN low wires may be open, shorted together, or shorted to power or ground between the OCS module and the network backbone.
A blown dedicated fuse, corroded ground eyelet, or damaged power feed wire prevents the OCS module from powering up to communicate.
Poorly installed aftermarket electronics tapping into the CAN bus can disrupt communication specifically with the OCS module.
Rarely, the powertrain control module’s internal CAN transceiver fails, though this would typically cause communication loss with multiple modules, not only the OCS.
The vehicle can be driven, but the passenger airbag may be disabled and will not deploy in a collision, so avoid carrying front passengers until the fault is repaired.
No. U0154 is almost never caused by a faulty PCM; the root cause is almost always the OCS module itself or wiring and connector issues under the passenger seat.
You can clear it, but if the underlying communication fault persists, the code and airbag warning light will return immediately or shortly after starting the vehicle.
The OCS module must be physically integrated with the seat’s weight-sensing bladder or strain gauges to measure occupant mass, requiring it to be mounted within the seat structure or immediately beneath it.