B3481

Code

Generic B — Body

Passenger Occupant Detection Sensor Circuit High

Brand: Generic

Type: B — Body

Views: UK: 13 EN: 25 RU: 18

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Page language: EN

Causes

Open or shorted wiring (short to battery/ignition 12 V) in the sensor circuit
Corroded, loose, or damaged connector at the occupant sensor or airbag control module
Failed/passenger occupant detection sensor (seat pad sensor)
Water ingress or contamination in the seat or sensor assembly
Poor or intermittent ground
Faulty passenger airbag/occupant classification module (ECU) or software error

Symptoms

SRS/airbag warning lamp illuminated
Passenger airbag disabled when it should be enabled (or enabled when it shouldn’t be)
Seat belt reminder or passenger presence indicator incorrect
Intermittent or persistent DTC stored (B3481)
Possible inability to complete occupant classification calibration

What to check

Read SRS/airbag module for stored codes and freeze frame with a capable scan tool
Visually inspect passenger seat, sensor pad area, and connectors for damage, corrosion, or debris
Check for water/moisture under the seat and dry if present
Check connector locking tabs and pin condition at the sensor and module
Backprobe sensor connector and measure signal, reference and ground voltages
Measure continuity and resistance of sensor wiring to detect shorts or opens

Signal parameters

Supply/reference voltage: typically ~5 V (varies by manufacturer) present at sensor connector with ignition ON
Expected sensor signal: typically 0.5–4.5 V in normal range (varies by sensor type and manufacturer)
Circuit high condition: sensor signal significantly above normal range or near supply voltage (close to reference or battery voltage)
Ground continuity: low resistance between sensor ground and chassis ground (typically
Open circuit: very high or infinite resistance in wiring or sensor element

Diagnostic algorithm

Use an OEM-capable scan tool. Record stored codes and freeze-frame data. Clear codes and see if B3481 returns.
With ignition OFF, visually inspect passenger seat area, connectors and harness for damage, contamination, or water ingress. Repair visible issues.
With ignition ON (follow SRS safety procedures—see vehicle manual; disable battery if required before disconnecting connectors), backprobe the sensor connector: verify reference voltage, signal voltage, and ground. Compare to expected values.
If signal is high, disconnect the sensor connector and re-check signal at the harness side. If high remains at harness, suspect wiring short to power or module fault. If signal goes normal, suspect sensor fault.
Perform continuity and short-to-power/ground checks on the sensor wiring between the sensor connector and the airbag/occupant module. Repair any chafed or shorted wiring.
Inspect and, if necessary, clean or replace corroded connectors and pins. Ensure proper locking and contact pressure.
If wiring and connectors are good, replace or swap the passenger occupant detection sensor with a known-good unit if available, then re-test.
After repair or replacement, perform OEM-specified occupant classification/seat calibration procedure using the diagnostic tool. Clear codes and confirm normal operation.
If code persists, suspect module fault and follow manufacturer guidance for module testing or replacement.
Safety note: Follow all SRS/airbag handling procedures in the vehicle service manual. Disable the battery and wait the specified time before disconnecting airbag connectors to avoid accidental deployment.