B3471

Code

Generic B — Body

Occupant Detection Sensor Circuit Fault (Passenger Seat)

Brand: Generic

Type: B — Body

Views: UK: 8 EN: 10 RU: 16

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Damaged, corroded or disconnected connector at the occupant detection sensor
Broken, pinched, shorted, or open wiring in the seat harness
Faulty occupant detection sensor assembly (seat cushion or sensor mat)
Faulty seat control module or airbag/occupant classification module
Water intrusion or contamination of the sensor mat
Improperly installed or non‑OEM seat or cushion

Symptoms

Airbag or SRS warning lamp illuminated
Passenger airbag disabled or enabled incorrectly
Seatbelt reminder or warning behavior abnormal for passenger seat
Stored code(s) related to occupant detection or seat module
Possible intermittent fault: warning lamp may come on and off

What to check

Read freeze frame and related SRS/OCS codes with a capable scan tool
Visual inspection of passenger seat, connectors, and wiring for damage or contamination
Check for water, debris or corrosion on the seat cushion/sensor mat
Verify connector engagement and terminal integrity at seat and module
Measure continuity and resistance of sensor circuit wiring to the module
Compare sensor resistance/voltage to manufacturer specifications if available

Signal parameters

Typical sensor type: resistive load cell/pressure mat or capacitive sensor (check service data)
Expected quiescent resistance/value: varies by manufacturer — often a specific resistance range (consult OEM spec)
Nominal reference voltage to sensor circuit: commonly 5 V reference from module
Signal voltage to module typically varies with occupancy; should not be open or short to battery/ground
Continuity: < few ohms for grounds, open circuit indicates broken wiring; high resistance on signal indicates a fault

Diagnostic algorithm

Verify and record all related DTCs and freeze frame data using an SRS-capable scanner. Note if fault is pending or permanent.
Perform a visual inspection of the passenger seat area: check for water, spilled liquids, aftermarket seat covers, or physical damage to the cushion.
With the ignition off, disconnect the passenger seat connector(s). Inspect pins for corrosion, bent pins, pushed pins, or foreign material. Reconnect and wiggle harness to check for intermittent failures.
Check power, ground, and signal reference at the seat connector with a multimeter: verify reference voltage (often 5 V) and a good ground per service manual.
Measure resistance of the occupant detection sensor mat per OEM procedure (bench test if necessary). Compare to spec. Look for open circuit or values out of range.
Backprobe the sensor signal while performing an occupancy test (person or test weight) and watch for expected change in signal voltage/resistance. Do not compromise safety — follow safe procedures and OEM test weights if provided.
If wiring or connectors are faulty, repair harness using correct splices, soldering, and shrink tubing or OEM repair terminals. Replace damaged connectors or pins.
If wiring and connectors check good but sensor values are out of spec, replace the occupant detection sensor/mat or seat module per OEM instructions.
After repair, clear codes and perform diagnostic relearn/calibration procedures required by the manufacturer for the occupant classification system. Re-scan to confirm code does not return.
If the code persists after sensor and wiring repairs, test/replace the occupant classification or SRS module as last resort and follow required programming/configuration steps.