Faulty passenger seat position sensor; Damaged or chafed wiring harness under the seat; Loose or corroded electrical connector at the sensor or BCM; Failed seat position sensor magnet or track; Water intrusion or debris in the seat track area; BCM internal fault or software issue

DTC codes / B03xx · Airbags, seats, doors, lights and comfort systems / B0320

B0320Passenger Seat Position Sensor Circuit

Q: What does code B0320 mean?

Passenger Seat Position Sensor Circuit. B0320 indicates that the body control module (BCM) or occupant detection module has detected a fault in the passenger seat position sensor circuit, which is used to determine the fore-aft location of the front passenger seat for airbag deployment logic. The computer monitors the sensor's signal voltage and sets this code when the voltage falls outside the expected range or the circuit is open or shorted.

B0320 indicates that the body control module (BCM) or occupant detection module has detected a fault in the passenger seat position sensor circuit, which is used to determine the fore-aft location of the front passenger seat for airbag deployment logic. The computer monitors the sensor's signal voltage and sets this code when the voltage falls outside the expected range or the circuit is open or shorted.

SystemBody

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

Airbag warning light illuminated on the instrument cluster
Passenger airbag may be automatically disabled even with an adult seated
Seat position memory or easy-entry feature may not function correctly
Often no symptoms besides the warning light
In some vehicles, a message on the driver information center indicating a restraint system fault

Common causes, most likely first

Faulty passenger seat position sensor
Damaged or chafed wiring harness under the seat
Loose or corroded electrical connector at the sensor or BCM
Failed seat position sensor magnet or track
Water intrusion or debris in the seat track area
BCM internal fault or software issue

How to diagnose and fix it

Inspect the seat position sensor connector and wiring for damage or corrosion
Check for technical service bulletins (TSBs) related to the seat position sensor circuit
Measure sensor resistance and voltage with a multimeter and compare to specifications
Verify sensor signal at the BCM using a scan tool with live data
Replace the seat position sensor if faulty
Repair or replace damaged wiring harness sections
Clear codes and perform a system relearn or calibration if required

Seat position sensor faults often misdiagnosed

A common mistake is replacing the seat position sensor when the real problem is a chafed wire under the seat that only shorts when the seat is moved.
The passenger seat position sensor is part of the occupant classification system (OCS) and can be affected by spilled liquids or debris in the seat track.
Some vehicles require a scan tool to recalibrate the occupant detection system after any seat component replacement, or the code will return.
A weak or dead battery can cause erratic sensor signals and set this code, so always check battery health first.
The code can be set by a faulty seat position sensor magnet that has weakened over time, even if the sensor itself tests good.

Can I keep driving with B0320?

The vehicle is generally safe to drive, but the passenger airbag may not deploy correctly in a crash, so have the fault diagnosed promptly and avoid carrying passengers in the front seat until repaired.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.