B005B

Code

Generic B — Body

Occupant Classification System Fault — Invalid Data

Brand: Generic

Type: B — Body

Views: UK: 14 EN: 21 RU: 11

AI status

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Page language: EN

Causes

Corroded/damaged connector or wiring under the passenger seat
Faulty occupant classification mat/sensor (open, short, or damaged traces)
OCS control module internal fault or firmware error
Loss or corruption of LIN/CAN communication between OCS and restraint control module
Contamination (water, spills) or mechanical damage to the seat cushion/mat
Failed or incomplete OCS calibration or software mismatch after module replacement

Symptoms

Passenger airbag status warning or passenger airbag OFF indicator illuminated
SRS/airbag warning light on dashboard
Passenger occupant classification state shows 'invalid' or 'unknown' in scan tool
Airbag may be incorrectly enabled/disabled for passenger seat
Possible intermittent behavior—code present then returns

What to check

Read stored and pending codes from SRS and OCS modules; record freeze-frame/live data
Inspect seat cushion and underside for visible damage, water ingress, or debris
Visually inspect and wiggle-test connectors, wiring harness, and seat rail harness grommets
Check for related communication codes on CAN/LIN networks
Confirm OCS calibration status and compare software/part numbers to service data
Observe live OCS parameters (occupant state, sensor zone values, module voltage/ground)

Signal parameters

OCS module supply voltage (VBATT) and ground integrity
Seat mat sensor zone resistances/voltages (per-zone raw values)
Occupant classification output state (Empty, Occupied, Child, Invalid/Unknown)
LIN/CAN messages: presence and periodicity of OCS frames (message IDs depend on vehicle)
Seatbelt buckle switch status and seat position sensor values (can affect classification)

Diagnostic algorithm

Use a capable scan tool to confirm B005B and check for related SRS/OCS/CAN/LIN codes; record live data and freeze frame.
Before working on SRS circuits follow manufacturer safety procedures (battery disconnect/time delay) and wear appropriate PPE.
Visually inspect passenger seat cushion, seams and underside for spills, burns, tears or foreign objects that can damage sensor mat.
Inspect connectors under the seat: unplug, inspect pins for corrosion, bent pins, contamination; reconnect and verify secure fit.
With connectors reconnected, monitor live sensor zone values while applying known weights to seat zones (using service procedure) to confirm sensible, stable readings and detect open/short zones.
Check wiring continuity and resistance from mat connector to OCS module; look for intermittent shorts to chassis ground, high resistance, or open circuits.
Verify OCS module power and ground at the connector with key on; correct any voltage supply or ground faults.
Check vehicle data bus health: verify OCS messages on LIN/CAN and confirm correct addressing and periodic messages. Repair bus faults if present.
If wiring and connectors are good but values are out-of-range, replace or repair the seat mat/sensor per manufacturer instructions.
After repairs, perform OCS sensor calibration/relearn using factory scan tool and clear codes; verify stable readings and confirm code does not return during test drive or acceptance tests.
If code persists after sensor/mat and wiring replacement and successful calibration, consider replacing OCS control module or pursuing manufacturer software update.