B2359

Code

Generic B — Body

Occupant Presence Sensor Circuit Fault — Front Passenger Seat

Brand: Generic

Type: B — Body

Views: UK: 1 EN: 0 RU: 1

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Causes

Open or shorted wiring between occupant presence sensor and control module
Corroded, loose, or damaged connector at the sensor or module
Faulty occupant presence sensor / pressure mat in the passenger seat
Water/moisture intrusion into the seat cushion or sensor assembly
Seat cushion removed, installed incorrectly, or damaged seat structure affecting sensor
Faulty airbag/occupant classification module or internal fault

Symptoms

SRS/Airbag warning light illuminated on instrument panel
Passenger airbag status indicator (ON/OFF) may be incorrect or show OFF when occupied
Seat belt reminder may not behave correctly for passenger side
Possible stored additional SRS or occupant classification codes
Intermittent fault that can appear/disappear with seat position changes

What to check

Scan vehicle with a compatible SRS/airbag-capable scan tool and read freeze frame/related codes
Visually inspect passenger seat cushion and underside for signs of water, damage, or repairs
Inspect connectors under passenger seat and at the airbag/occupant module — check for corrosion, bent pins, pushed out terminals, or foreign material
Visually inspect wiring harness along seat tracks and through the door sill for chafing, breaks, or pinches
Check if passenger airbag status lamp behavior changes when someone sits in seat (observe SRS indicators)

Signal parameters

Reference supply typically provided by SRS/occupant module: often a 5 V reference and ground (verify with OEM data)
Occupant sensor signal: commonly an analog voltage in the 0–5 V range that varies with load or a variable resistance/capacitance output — when unoccupied the signal is in a defined "empty" range, and when occupied it shifts into an "occupied" range (exact thresholds are OEM-specific)
Open-circuit: infinite resistance / no signal; shorted to ground: ~0 V; shorted to Vref: ~reference voltage (e.g., ~5 V) — verify with manufacturer values

Diagnostic algorithm

Follow all manufacturer SRS safety procedures before inspecting or servicing (use approved procedure for disabling SRS/airbag system; many vehicles require battery disconnect and a wait period). Do not probe airbag inflators or wiring in a manner not allowed by OEM guidance.
Use a scan tool to record the B2359 code, related SRS codes, and freeze frame data; note any history or intermittent flags.
Perform a visual inspection under the passenger seat: connectors, sensor mat, wiring routing, seat tracks, and any signs of water intrusion or repair.
With SRS deactivated per OEM instructions, disconnect the passenger seat sensor connector and inspect pins for corrosion, looseness, or damage; reconnect securely and recheck code.
Backprobe the sensor connector (with SRS active handling per OEM) or follow OEM procedures to measure reference voltage, ground continuity, and sensor signal voltage with ignition ON and with/without occupant on the seat. Compare to manufacturer-specified ranges (typically a 0–5 V analog range or a measurable resistance change when loaded).
Perform continuity/resistance checks on the harness between the sensor connector and the occupant classification module; wiggle wiring while monitoring for intermittent changes.
If wiring and connectors test good, swap or bench-test the occupant presence sensor (if removable and permitted by OEM) or replace with a known-good sensor/mat per manufacturer instructions.
After repair or replacement, clear codes with the scan tool, perform any required occupant classification or SRS system recalibration/programming as specified by the OEM, then retest for code recurrence and correct passenger airbag indicator operation.
If fault persists and wiring and sensor are good, consider module fault — consult manufacturer for module testing, reprogramming, or replacement.