B1184

Code

Generic B — Body

Passenger occupant detection sensor circuit failure

Brand: Generic

Type: B — Body

Views: UK: 24 EN: 28 RU: 31

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Page language: EN

Causes

Loose, disconnected or corroded connector(s) at the occupant sensor or airbag control module
Damaged wiring harness under the passenger seat (chafing, broken conductors, short to ground/vehicle power)
Faulty occupant detection sensor mat (pressure/load cell, film or electronic sensor element)
Water ingress or contamination of the sensor mat or connector
Improperly installed seat cover or aftermarket seat heater that interferes with the sensor
Fault or software issue in the airbag/occupant detection control module

Symptoms

SRS/airbag warning lamp illuminated on the dash
Passenger airbag status message shows 'OFF' or 'Unavailable' even with an occupant present
Passenger airbag indicator behaves incorrectly or flashes
Intermittent SRS lamp or occupant detection behavior that changes with seat position or pressure
Possible stored history of intermittent faults related to seat wiring or sensor

What to check

Use an OBD or SRS-capable scan tool to read stored/active codes and view live passenger-occupant-sensor data (passenger weight or presence status).
Visually inspect connectors under the passenger seat and at the airbag control module for corrosion, water, or bent pins.
Inspect the wiring harness routing under the seat for chafing, pinches or broken conductors (especially at seat rails and recliner pivots).
Check for recent seat repairs, swapped seats, or aftermarket seat covers/heaters that may affect the sensor.
Verify fuses and related power/ground circuits to the airbag/occupant module.
If safe and per manufacturer instructions, measure circuit continuity and resistance of the sensor harness; look for open or shorted conductors.

Signal parameters

Occupant sensor typically uses a reference voltage (commonly a 5 V reference) and a return/signal circuit — the signal should change when weight is applied to the seat.
Resistance or sensor output should vary smoothly with applied load (no open circuit or abrupt discontinuities).
No short to ground or battery voltage on the sensor signal/return circuits.
Live data from the airbag module should show occupant presence/weight values that respond when a known test weight is placed on the seat.
Current draw on the sensor circuit is usually low; an abnormally high current may indicate a shorted element.

Diagnostic algorithm

Safety first: Before working on SRS components, follow OEM SRS safety procedures. Disable the battery negative, wait the manufacturer-specified time before accessing connectors (commonly 90 seconds to several minutes), and wear appropriate PPE.
Connect an SRS-capable scan tool. Read and record all SRS/airbag DTCs and freeze-frame data. Note whether B1184 is active or stored and any related codes.
With the scan tool monitoring occupant-presence data, perform a live test: have a helper sit in the passenger seat or place a calibrated test weight and observe whether the module registers presence/weight and whether the code reappears.
Visually inspect the passenger seat: remove seat trim as needed to access the sensor mat, connectors and harness routing. Look for water staining, contamination, sewn-in wrinkles, or damaged elements in the mat.
Inspect and lightly tug connectors under the seat and at the airbag module. Look for bent pins, corrosion, or loose terminals. Repair or clean contacts as required.
Inspect wiring along the full harness route for breaks, melted insulation, or chafing — especially where the harness passes through moving joints (rails, recliner). Repair broken wires or damaged insulation with proper crimp/splice or solder and appropriate insulation.
With connectors exposed and per OEM instructions, measure continuity and resistance of sensor circuits. Compare behavior with and without load on the sensor. An open or infinite resistance, or no change with applied load, points to a faulty sensor or open circuit.
If available, use an oscilloscope to verify the signal waveform and reference voltage while applying weight. Look for stable reference voltage and a signal that changes proportionally with load.
If wiring and connectors test good but the sensor does not respond correctly, replace the passenger occupant sensor mat or the sensor module following manufacturer procedures.
If replacement of the sensor does not clear the fault, suspect the airbag control module or a software/configuration issue — verify calibration or module programming and check for updates or reflash procedures in service information.
After repairs, clear codes, perform the occupant detection functional/learn procedure if required, and confirm repair by re-checking live data and ensuring the SRS lamp extinguishes.