B1094

Code

Generic B — Body

Occupant Classification System (OCS) Circuit Malfunction

Brand: Generic

Type: B — Body

Views: UK: 16 EN: 22 RU: 16

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Page language: EN

Causes

Damaged or disconnected seat occupant sensor (seat mat or load cell)
Broken, chafed or corroded wiring in the seat harness (open, short to ground or short to battery)
Poor or corroded connector terminals at the sensor or SRS control module
Faulty OCS module or SRS/airbag control module
Water intrusion or contamination in the seat cushion or connector
Failed sensor electronics (internal short/open)

Symptoms

SRS / airbag warning lamp illuminated
Passenger airbag status message incorrect or passenger airbag disabled when seat occupied
Seat belt reminder or occupant detection warning
Possibly no obvious seat-related symptoms other than stored DTC
Intermittent warnings that change when seat is moved or harness is disturbed

What to check

Read stored DTCs and freeze-frame data with an appropriate SRS-capable scan tool; note any related codes
Visually inspect the seat cushion, seat base, and wiring harness for damage, pinched wires, or water contamination
Inspect and reseat connectors at the occupant sensor and the airbag/SRS control module; check for bent pins and corrosion
Perform wiggle test while monitoring live sensor values to check for intermittent faults
Measure power supply and ground at the sensor connector with ignition on
Measure resistance/continuity of sensor circuit to detect opens or shorts

Signal parameters

Reference/power supply: typically ignition-switched 12 V or a regulated 5 V reference (verify with vehicle-specific data)
Ground: good chassis ground at sensor connector (near 0 Ω to vehicle ground)
Sensor output: resistive or load-cell output — open circuit (OL/infinite Ω) indicates broken circuit; short to ground ~0 Ω indicates wiring short
CAN/LIN bus (if used): CANH ~2.5 V idle, CANL ~2.5 V idle; active states around 3.5 V / 1.5 V respectively — check bus messages with scanner
Expected behavior: stable sensor value when unoccupied and when occupant weight applied; noisy, drifting or frozen values indicate fault

Diagnostic algorithm

Connect SRS-capable scan tool, read and record DTCs, live data and freeze-frame. Note any additional SRS or communication codes.
Clear codes and perform a road/seat test to see if the code returns; observe live OCS sensor values while applying known loads (e.g., a known weight) if safe to do so.
Visually inspect seat cushion and sensor area for damage or contamination. Inspect wiring harness routing, and look for pinched or chafed wires where the harness passes through the seat frame.
With battery disconnected (if required by manufacturer), disconnect sensor connector(s) and inspect terminals for corrosion, bent pins, or water ingress. Repair or replace connector as needed.
With ignition ON and appropriate safety procedures for SRS, measure reference voltage and ground at the sensor connector. Compare readings to vehicle specifications. Repair power/ground faults.
Measure resistance/continuity of the sensor circuit from the connector back to the module. An open, short to ground or short to battery indicates wiring repair is required.
If sensor wiring and connectors are good, bench-test or substitute the occupant sensor (or module) with a known-good unit if available, then re-check codes and live data.
If wiring and sensor check good, inspect SRS/airbag control module connections and communications. Check for related communication codes (U-codes). Replace or reprogram control module only after confirming upstream components.
After repair or component replacement, clear codes, perform required OCS calibration or zeroing procedure per manufacturer, then confirm fault does not return and SRS lamp remains off.
If intermittent or complex electrical issues persist, consult vehicle-specific wiring diagrams and manufacturer technical service bulletins (TSBs).

Likely causes

Wiring damage in the seat harness near the seat base or under the seat (most common)
Corroded/loose connector at the occupant sensor or airbag control module
Failed occupant sensor (seat mat/load cell)
Fault in the SRS control module or a communication fault preventing valid sensor data