B10A2

Code

Generic B — Body

Occupant Classification System Sensor Communication Fault

Brand: Generic

Type: B — Body

Views: UK: 29 EN: 36 RU: 33

AI status

Completed

ready

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Page language: EN

Causes

Damaged or disconnected wiring between the seat sensor mat and occupant classification module
Loose, corroded or pushed-back connector pins at the seat, airbag control module or junctions
Failed occupant classification sensor mat or seat module (internal short/open)
Loss of power or ground to the occupant classification module
Faulty occupant classification module (control unit)
Intermittent/poor LIN or CAN bus communication affecting OCS data

Symptoms

SRS / airbag warning lamp illuminated
Passenger airbag status (enabled/disabled) may be incorrect or unavailable
Passenger presence/weight readout incorrect or not shown in diagnostic data
Inability to toggle passenger airbag on/off when expected
Additional communication or restraint system DTCs may be present
Possible audible chime or warning depending on vehicle

What to check

Retrieve freeze frame and stored DTCs with a capable scan tool; note any related body or bus communication codes
Visually inspect seat harness, connectors and routing for damage, corrosion, or water ingress
Verify battery voltage with ignition ON; check power and ground at the occupant classification module
Check for continuity and resistance of sensor mat leads per service data (watch for opens or shorts)
Use a scan tool to monitor OCS live data and watch for changes while gently moving the seat (wiggle test)
Inspect and test LIN/CAN bus communication to the module (message presence, error frames, bus off)

Signal parameters

Supply voltage to OCS module: typically ~11–14 V with ignition ON
Ground continuity: low resistance to vehicle chassis ground
Sensor mat resistance: should not be open (infinite) or shorted to ground/battery — compare to manufacturer spec
Data bus: OCS messages present on LIN or CAN as applicable; CAN idle approx. 2.5 V on each line, differential signal present
Communication rate and message IDs are manufacturer-specific; expected periodic occupancy messages when system initialized
Fault conditions often produce no data, intermittent messages, or invalid/unplausible occupant values

Diagnostic algorithm

Connect a diagnostic scanner capable of reading airbag/occupant classification module data. Record all DTCs and freeze frame data.
Inspect seat area and connectors: remove trim as needed and look for pushed-back pins, corrosion, or damage to harness and connectors.
Verify battery voltage and check the fuses/power feed to the occupant classification module and related modules.
With connector(s) disconnected, visually inspect pins for damage and measure for continuity/resistance between the sensor mat leads and module connector.
Reconnect and monitor live OCS data while performing a wiggle test on wiring and moving the seat through its range — note any communication dropouts or changes.
If bus-related, use an oscilloscope or appropriate scan tool to verify CAN/LIN signals and look for error frames or a bus-off condition.
If sensor mat wiring is OK but communication remains faulty, swap or bench-test the occupant classification module per manufacturer procedures, or replace with a known-good unit if available.
After repair or component replacement, clear codes and perform required occupant classification calibration/initialization per factory service procedure.
Re-scan for codes and confirm stable live data and that the SRS warning lamp extinguishes after ignition cycles.

Likely causes

Seat harness connector pushed into seat (pins bent or corrosion)
Broken wire in the seat belt buckle or seat cushion harness from seat movement
Open or short in the sensor mat wiring due to seat heater installation or repair
Faulty occupant classification module following impact or exposure to moisture
Bus communication fault (LIN/CAN) due to shared grounding or module failure
Module lost supply voltage (blown fuse or disconnected battery terminal during service)

Fault status

⚠️ Status

Occupant Classification System sensor communication fault — the OCS sensor/module is not communicating correctly or is providing invalid data. SRS/airbag system may flag fault and affect passenger airbag operation.

🔴 Repair difficulty: Hard

⏱️ Diagnostic time: 1-3 hours