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Severity: High Code type: Manufacturer-specific (Kia)

Kia B1764 Code: Occupant Detection – Body Sense Mat Defect

Kia's passenger seat detection unit reports a broken sensor mat, so airbag suppression can't be trusted.

Safety first · Consult a professional

  • Airbag (SRS) circuits must only be serviced by a professional. Never probe airbag connectors — accidental deployment causes serious injury.

At a glance

Severity: 4/5 – High4/5

Severity: High

Meaning
Occupant Detection – Body Sense Mat Defect
System
Body Systems · Body
Safe to drive?
With caution
Typical repair cost
$0–$1,700
DIY difficulty
Professional only

US-market Kias decide whether to allow the front passenger airbag with an occupant detection system (ODS): a thin sensor mat in the passenger seat cushion, which Kia calls the body sense mat, wired to a small ODS control unit under the seat. B1764 is stored in that ODS unit when the mat or its short harness fails the unit's self-check; the airbag control module usually shows its own summary code at the same time, typically B1490 for an OCS/ODS defect. Kia has recalled some 2015–2018 Sedona models with manual passenger seats because the harness between mat and ODS unit could crack from repeated bending when someone sat down, and B1764 was one of the codes named for that condition. On Sorento, Optima, Forte and Sedona the fix is often a cushion with a new mat rather than a separate sensor.

Can I keep driving? The car drives normally, but the passenger airbag may be suppressed for an adult or, worse, not suppressed for a child. Keep children in the rear seat and have the VIN checked for recalls before paying for repairs.

How to read B1764

How to read B1764B11273644
  1. B Body
  2. 1 Manufacturer-specific
  3. 7 Body Systems
  4. 64 Specific fault

Symptoms

  • Airbag warning light on, often with B1490 in the airbag module
  • Passenger airbag indicator shows OFF with an adult or ON with the seat empty
  • Indicator changes as the passenger moves or when the seat is bounced
  • Problem started after items were stored under the seat or the seat was removed
  • Code comes back right after clearing

Possible causes

Ranked by how often each cause is behind this code (editorial estimate).

  1. Broken wire or connector in the short harness between the mat and the ODS unit under the seat 40%
  2. Failed body sense mat inside the seat cushion 30%
  3. Harness pinched by objects under the seat or during seat removal 14%
  4. Aftermarket seat heater or cover disturbing the mat 9%
  5. Faulty ODS control unit 7%

Diagnosis step by step

Diagnostic flow: B17641Run the VIN for recalls2Read both modules3Clear under the seat4Inspect the mat harness (batteryoff)5Replace mat or cushion andrecalibrate

  1. Run the VIN for recalls

    Check your VIN on Kia's owner site and at NHTSA. The ODS harness recall covers certain Sedona models, and dealers repair or replace the cushion free when a vehicle is included.

  2. Read both modules

    Scan the airbag module and the ODS unit separately. B1490 in the airbag module plus B1764 in the ODS unit confirms the mat circuit; other ODS codes point at the unit's power or communication.

    Tools: OBD-II scanner

  3. Clear under the seat

    Remove umbrellas, bottles and anything pushed under the passenger seat. Objects there can press on or snag the harness running from the cushion to the ODS unit.

    Tools: Flashlight

  4. Inspect the mat harness (battery off)

    With the battery disconnected and the waiting time observed, a technician tilts the seat and inspects the harness clips and the connector at the ODS unit. A crack where the harness bends under the cushion is the classic Sedona failure.

    Tools: Flashlight

  5. Replace mat or cushion and recalibrate

    If the harness is intact but the mat reads open, the seat cushion with integrated mat is replaced. The ODS is then reset with an empty seat on the scan tool and verified with an adult passenger.

    Tools: OBD-II scanner

Repair options & costs

RepairDIY?Estimated cost
Recall inspection and harness clip removal (if included) No $0
SRS/ODS diagnosis No $100–$180
Mat-to-ODS harness or connector repair No $150–$400
Passenger seat cushion with body sense mat No $700–$1,700
ODS control unit replacement and calibration No $400–$900

Rough US estimates for parts and labor; shop rates vary by region. Not a quote.

Notes by brand

Hyundai

Hyundai's older occupant classification systems report a failed seat mat as B1448 instead, and older Kias from the same era such as the Optima and Rio do the same, so the code number depends on which generation of passenger detection the car has.

Emissions / smog test impact

Depends

B1764 doesn't affect a state emissions test, but a lit airbag warning light can fail a state safety inspection.

Frequently asked questions

Why does my scan tool show B1490 and not B1764?

The airbag module reports a general occupant detection defect (B1490), while the specific B1764 lives in the separate ODS unit under the seat. You need a tool that can read the ODS unit to see it.

Is my Sedona part of the ODS recall?

Only a VIN check can tell you. The recall covered certain Sedona models with a manual front passenger seat, and the dealer also replaces the cushion when the harness is already damaged.

Can the passenger airbag deploy with B1764?

You can't rely on it either way. Depending on the failure, the system may suppress the airbag for an adult or fail to suppress it for a child, which is why children should ride in the back until it's fixed.

Why is the repair a whole seat cushion?

The body sense mat is built into the cushion and Kia's own repair procedure replaces the cushion as an assembly when the mat circuit is damaged. That's why the cost jumps when the mat itself, not the harness, has failed.

Sources