B2393

Code

Generic B — Body

Passenger Seat Occupant Detection Circuit Fault

Brand: Generic

Type: B — Body

Views: UK: 11 EN: 11 RU: 13

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in occupant detection sensor wiring (open, short to ground, short to battery)
Poor connector pin contact or corroded terminals at seat or airbag module
Faulty occupant detection sensor (pressure/weight mat, load cell, or sensor array)
Faulty seat control module or occupant classification module
Water intrusion or contamination of seat cushion sensor
Intermittent wiring fault due to seat movement or connector strain

Symptoms

Passenger airbag status lamp illuminated or airbag disabled for passenger side
Airbag warning lamp on the instrument cluster
Passenger seat belt reminder incorrect or not functioning
Stored DTC B2393 (may be accompanied by other SRS/occupant codes)
Possible intermittent behavior when passenger shifts position

What to check

Read all stored codes and freeze frame data with an OEM-capable scan tool; record live data for passenger occupancy status
Visually inspect seat cushion, connectors, and wiring harness under the seat for damage, corrosion or loose pins
Perform wiggle test on seat wiring while monitoring live data to reproduce fault
Check for water intrusion or signs of contamination in the seat cushion
Verify any recent seat repairs or aftermarket covers that could affect sensor function

Signal parameters

Occupant sensor signal type: resistance, voltage, or CAN message depending on vehicle (typical sensor voltage 0–5 V for active sensors)
Open-circuit: infinite resistance or no voltage signal reported; Short-to-ground: ~0 V; Short-to-battery: near battery voltage (approx 12 V)
Seat mat sensor resistance or impedance may change with weight — expect measurable, repeatable change when load applied
CAN/serial data: occupant classification module should publish valid status (occupied/unoccupied/child) — check message presence and values

Diagnostic algorithm

Connect a diagnostic scanner and read stored SRS/occupant detection codes and live data. Note whether the module reports open/short/implausible signal.
Visually inspect the passenger seat cushion, seat pan area and underside for water, foreign objects, or visible damage to the sensor mat or wiring.
With battery voltage present, inspect and gently unplug/replug the seat sensor connector(s); check for bent pins, corrosion, or water intrusion. Reconnect securely.
With scanner monitoring the occupant status or sensor voltage, perform a wiggle test of the harness and move the seat through full travel to try to reproduce the fault. Observe for intermittent changes.
Measure at the sensor connector: supply/reference voltage, signal voltage, and ground continuity. Compare to expected generic ranges (0–5 V for signal; 12 V or 5 V reference as applicable). Check for open/short conditions.
If the sensor uses resistance/strain gauges, measure resistance/impedance across sensor terminals and observe change when applying known weight or pressure to the cushion. Note inconsistent or infinite values as fault indication.
If wiring and connectors test good, consult OEM service data for specific sensor resistances and test procedures. If available, swap with a known-good seat module or sensor to confirm failure.
Replace only confirmed faulty components: repair damaged wiring, replace connector terminals, replace the occupant detection mat/sensor or occupant classification ECU per OEM instructions. After repair, clear codes and verify restoring correct occupant status and no abnormal SRS warnings.
If repairs require seat or airbag module removal, follow safe SRS procedures (battery disconnect, wait time, manufacturer precautions) and use appropriate restraints-handling tools.

Likely causes

Damaged or twisted wiring harness under the seat (common with seat slide travel)
Corroded or loose connector at the seat occupancy sensor or SRS module
Failed occupant detection mat or sensor pad inside the seat cushion
Faulty occupant classification ECU or internal module fault

Fault status

⚠️ Status

Passenger seat occupant detection circuit fault — the occupant sensor circuit is reporting an open/short or implausible signal. The passenger airbag/occupant classification functions may be disabled until the fault is corrected.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours