B1672 — Seat Driver Occupied Input Circuit Failure #

The code description may vary depending on the vehicle manufacturer (OEM). Below are known label variations for this DTC:

• Seat Driver Occupied Input Circuit Malfunction (Ford, Lincoln, Mercury)
• Driver Seat Occupancy Sensor Circuit Fault (Hyundai, Kia)
• Driver Presence Detection Circuit Error (GM, Chevrolet, Cadillac)

Summary of the B1672 Code #

The B1672 code relates to a fault in the driver seat occupancy detection circuit. This system uses sensors—often referred to as “seat occupancy sensors”—to determine if the driver’s seat is occupied, which is crucial for airbag deployment, seat belt reminders, and sometimes vehicle startup authorization. When the vehicle’s control module (such as the Occupant Classification Module or Restraints Control Module) detects an abnormality in the circuit, it sets the B1672 code and may illuminate a warning light. It is important to address this code promptly, as it can impact the functionality of safety systems. The specific diagnostic and repair approach can vary based on the OEM’s design and the seat system configuration.

Frequent Symptoms for Code B1672 #

Drivers may notice several signs when the B1672 code is present. Often, these symptoms are subtle but can have significant implications for safety. Watch for:

• Airbag warning light illuminated on the dashboard
• Seatbelt warning chimes or indicator stays on even when buckled
• Disabling of front airbag or altered airbag deployment behavior
• Driver seat occupancy not detected when someone is seated
• Occasional no-start condition in push-button start vehicles (rare)

Probable Causes for Code B1672 #

The most frequent causes behind a B1672 code typically stem from issues in the seat sensor circuit. Here are the likely culprits, listed in order of frequency:

1. Faulty driver seat occupancy sensor (sensor degradation or damage)
2. Damaged or disconnected wiring/connectors under the seat (loose, pinched, corroded, or broken wires)
3. Fault in the Occupant Classification Module (OCM) or associated control unit
4. Water intrusion or contamination in the seat base or connector area
5. Seat cushion or trim replacement without proper sensor recalibration

Step-by-Step Diagnosis for Code B1672 #

Accurately diagnosing B1672 requires a systematic approach, as guessing can lead to wasted time and unnecessary part replacement. Follow these steps:

1. Verify the code using a professional-grade scan tool; check for related DTCs.
2. Visually inspect all wiring and connectors under the driver seat for damage, corrosion, or loose connections.
3. Check the seat occupancy sensor with a digital multimeter (refer to OEM specs for resistance/voltage values).
4. Test the Occupant Classification Module for proper power, ground, and data communication.
5. Clear the code and perform a road test. Observe if the code returns or if symptoms persist.
6. If necessary, consult manufacturer service information for advanced circuit testing or re-calibration procedures.

Possible Repairs for Code B1672 #

The correct repair depends on the root cause found during diagnosis. Always address the most likely and cost-effective issues first:

• Repair or replace damaged wiring or connectors beneath the driver seat
• Replace the driver seat occupancy sensor if faulty or out of specification
• Clean or dry connectors if water or corrosion is found
• Recalibrate the seat occupancy system after sensor or seat cushion replacement (using a diagnostic scan tool per OEM instruction)
• Replace the Occupant Classification Module if diagnosed as defective

Is It Safe to Drive with Code B1672? #

Driving with a B1672 code is not recommended, especially if the airbag warning light is on. This fault can compromise the effectiveness of the supplemental restraint system (SRS), potentially preventing the airbags from deploying correctly in a collision. While the vehicle may still be drivable, the safety systems may not function as designed, putting occupants at risk. For your safety, have the issue diagnosed and repaired as soon as possible.

Vehicles Most Commonly Affected by Code B1672 #

B1672 is encountered across various makes and models, especially those using advanced seat occupancy detection technology. The code appears most frequently on:

• Ford (Fusion, Explorer, F-150, Escape, Taurus)
• Lincoln (MKZ, Navigator)
• Hyundai (Sonata, Elantra, Santa Fe)
• Kia (Optima, Sorento, Forte)
• General Motors (Chevy Malibu, Cadillac CTS, GMC Acadia)

Common Mistakes & Best Practices for Code B1672 #

Misdiagnosis or improper repairs can lead to recurring issues or even worsen the problem. Here are frequent errors and tips:

• Replacing the airbag module without verifying sensor and wiring integrity
• Neglecting to check under-seat connectors, especially after moving or cleaning under the seat
• Ignoring recalibration procedures after seat or sensor replacement
• Assuming the issue is always the sensor, when it’s often a wiring or connector fault
• Using generic scan tools that cannot read proprietary OEM SRS codes or perform calibrations

Quick FAQ for Code B1672 #

Can I reset the B1672 code myself by disconnecting the battery?
Disconnecting the battery may clear the code temporarily, but if the underlying issue is not fixed, the code and warning light will return. Proper diagnosis and repair are necessary.

Is it expensive to fix a B1672 code?
Costs vary. Simple wiring repairs or connector cleaning are inexpensive, but sensor or module replacement and required recalibration by the dealer may increase costs. Always start with a thorough diagnosis to avoid unnecessary expenses.