B2630

Code

Generic B — Body

Passenger Seat Occupant Classification Sensor Circuit Malfunction

Brand: Generic

Type: B — Body

Views: UK: 12 EN: 17 RU: 10

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Page language: EN

Causes

Loose, corroded or disconnected connector at the occupant classification sensor (seat cushion/seat module).
Damaged wiring harness (open, short to ground, short to battery, chafing).
Water/moisture intrusion into seat cushion or connector.
Faulty occupant classification sensor (mat or module) or sensor PCB.
Faulty airbag (SRS) control module or connector.
Aftermarket seat covers, cushions or repairs altering sensor behavior.

Symptoms

SRS / airbag warning lamp illuminated on dash.
Passenger airbag indicator showing 'off' or incorrectly disabled.
Diagnostic trouble code B2630 stored in SRS control module.
Possible inability to correctly detect passenger presence or weight classification.
Intermittent SRS lamp or changing passenger airbag status when seat is moved/occupied.

What to check

Use an OBD-II / SRS-capable scan tool to read stored and pending SRS codes and freeze frame data.
Verify passenger airbag on/off status with known good occupant (using service tool or vehicle indicator).
Visually inspect seat cushion, connectors and wiring for corrosion, damage, pin deformation or loose pins.
Check for water damage or staining on the seat cushion and connectors.
Wiggle test wiring and connectors while monitoring the code or sensor signal for intermittent faults.
Confirm no aftermarket seat covers or objects are interfering with the sensor mat.

Signal parameters

Sensor system typically uses a reference supply (commonly ~5 V) and ground; signal voltage varies with occupant load (0–5 V range typical).
Expect stable reference voltage present at sensor connector with ignition ON (compare to service data).
Signal voltage or resistance should change predictably when weight is applied/removed from seat cushion.
No continuity between signal and battery positive or chassis ground (no shorts).
Exact voltage/resistance ranges are manufacturer-specific — compare to vehicle service manual values.

Diagnostic algorithm

Observe SRS safety procedures before any work: disable battery negative, wait specified time per manufacturer, or follow approved SRS deactivation steps.
Connect an SRS scan tool and record codes, freeze frame and live data for the occupant classification sensor.
Inspect the seat cushion, sensor mat, harness routing and connectors for damage, corrosion, moisture or pin push-out. Repair any visible damage.
Backprobe the sensor connector with ignition ON (and SRS system energized per service manual) to verify reference voltage, ground continuity and signal behavior while an assistant sits on the seat or applies known weight. Compare values to service data.
Perform wiggle/drive-sim tests to reproduce intermittent faults; monitor live data for dropouts or abrupt signal changes.
If wiring is suspect, perform continuity and insulation-resistance checks between sensor pins and SRS ECU pins; repair splices or damaged sections.
If wiring and connectors are good, replace the occupant classification sensor mat/module. Reconnect and clear codes.
After repair, perform required SRS module resets/calibrations and verify code does not return. Re-run scan and re-check for stored/active codes and proper passenger airbag operation.
If code persists after sensor replacement, consider SRS control module fault and consult factory service information for module testing or replacement.

Likely causes

Corroded/loose connector under seat or at seat control module.
Harness pin damaged by seat movement (short during seat travel).
Moisture ingress in seat cushion sensor mat causing intermittent shorts.
Failed occupant classification mat/sensor assembly.
Intermittent connection from a poor splice or terminal.

Fault status

⚠️ Status

Stored when the passenger seat occupant classification sensor circuit shows open/short/abnormal signal; SRS warning lamp ON and passenger airbag may be disabled.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours

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