B013C

Code

Generic B — Body

Occupant Detection Sensor Circuit Malfunction

Brand: Generic

Type: B — Body

Views: UK: 2 EN: 0 RU: 0

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Causes

Broken, pinched or chafed wiring in the sensor harness
Loose, corroded or disconnected connector at the sensor or occupant classification module (OCM)
Failed occupant detection sensor (pad/pressure/capacitance sensor)
Faulty occupant classification module or internal electronics
Water/moisture or foreign object contamination in the seat cushion or connector
Previous seat repairs or aftermarket seat covers interfering with sensor

Symptoms

Passenger airbag status lamp may be illuminated or show 'off' incorrectly
Airbag readiness or supplemental restraint system (SRS) warning light on dash
Passenger airbag disabled when it should be enabled (or vice versa)
Possible diagnostic trouble codes related to OCM or occupant sensors
Inconsistent or intermittent passenger presence detection

What to check

Read DTCs and live data with a dealer-level or capable scan tool; record freeze frame and related codes
Visual inspection of seat bottom and back for moisture, damage or foreign objects
Inspect connectors and wiring harness under seat for corrosion, bent pins, broken wires or poor routing
Verify proper power (reference voltage) and ground at the occupant detection module and sensor connector
Monitor sensor signal data while placing known weight/object on seat (or having passenger sit) to confirm response
Wiggle test wiring/connectors while monitoring live data to find intermittent faults

Signal parameters

Reference supply typically 5 Vdc (varies by manufacturer) to sensor/module
Sensor signal expected to vary with load — commonly 0–5 V or a resistance change across sensor elements
Open circuit detected as very high resistance or no voltage signal
Short to ground shows near 0 V; short to battery shows near supply voltage
Intermittent or noisy signal will appear as erratic voltage or rapidly fluctuating values on live data

Diagnostic algorithm

Connect a scan tool, read and record B013C plus any related codes and freeze frame. Note vehicle make/model-specific data and OCM status.
Check for technical bulletins or software updates related to occupant detection for the specific vehicle.
Perform visual inspection of seat area and connectors for moisture, dirt, damage, or aftermarket items interfering with sensors.
With battery stable, inspect and secure connectors at the occupant detection sensor(s) and module; check for bent pins, corrosion, or water intrusion.
Backprobe the sensor connector and verify reference voltage, signal voltage and ground presence per manufacturer values. Compare to expected ranges and observe while loading the seat.
Check continuity and resistance of wiring between sensor and module with multimeter; look for opens, shorts to ground/battery, or high resistance.
Monitor live sensor data while applying known weight or having an assistant sit/stand to confirm sensor response. Note any lack of change, slow response, or noise.
Perform wiggle test of harness and connectors while observing live data to reveal intermittent faults.
If sensor wiring and connectors are good but signal is out of spec, try swapping sensors (if the system and vehicle allow) or replace the suspect occupant detection sensor.
If sensor replacement does not correct the fault, test module power/ground and communication; if module faults persist, consider replacing or reprogramming the occupant classification module per manufacturer procedures.
After repairs, clear codes, perform any required calibration or occupant sensor learning procedure, then verify with a road test or repeated load checks and re-scan for reappearance of DTC.