Faulty passenger seat belt buckle switch assembly, which is the most common cause due to wear or contamination.; Damaged or pinched wiring between the buckle switch and the body control module, often under the seat or at the buckle anchor.; Corroded or loose electrical connector at the buckle switch or at the BCM harness.; Water intrusion or spill damage affecting the buckle switch or connector.; Body control module internal fault, though this is less common than switch or wiring problems.; Aftermarket accessories or previous repairs that tapped into the seat belt circuit incorrectly.

DTC codes / B01xx · Airbags, seats, doors, lights and comfort systems / B0154

B0154Passenger Buckle Switch Circuit Malfunction

Q: What does code B0154 mean?

Passenger Buckle Switch Circuit Malfunction. B0154 means the body control module (BCM) has detected an abnormal condition in the passenger seat belt buckle switch circuit, such as an open, short, or out-of-range signal. The computer expects a specific voltage or resistance from the buckle switch when the seat belt is latched versus unlatched, and it has seen a value outside that expected range for a set period of time.

B0154 means the body control module (BCM) has detected an abnormal condition in the passenger seat belt buckle switch circuit, such as an open, short, or out-of-range signal. The computer expects a specific voltage or resistance from the buckle switch when the seat belt is latched versus unlatched, and it has seen a value outside that expected range for a set period of time.

SystemBody

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyIntermediate

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The seat belt warning light stays on or flashes even when the passenger seat belt is buckled.
The passenger seat belt chime may sound continuously or not at all, depending on the failure mode.
The airbag warning light may illuminate because the occupant classification system relies on buckle status.
The passenger airbag may be disabled or enabled incorrectly, as the system uses buckle status to decide deployment strategy.
Often no symptoms besides the warning light, especially if the fault is intermittent or only affects the buckle switch signal.
Remote start or other convenience features that depend on seat belt status may not work properly.

Common causes, most likely first

Faulty passenger seat belt buckle switch assembly, which is the most common cause due to wear or contamination.
Damaged or pinched wiring between the buckle switch and the body control module, often under the seat or at the buckle anchor.
Corroded or loose electrical connector at the buckle switch or at the BCM harness.
Water intrusion or spill damage affecting the buckle switch or connector.
Body control module internal fault, though this is less common than switch or wiring problems.
Aftermarket accessories or previous repairs that tapped into the seat belt circuit incorrectly.

How to diagnose and fix it

Inspect the passenger seat belt buckle and its connector for physical damage, corrosion, or debris, and clean or reseat as needed.
Use a scan tool to read live data for the passenger buckle switch status while latching and unlatching the belt to confirm the signal changes.
Measure resistance across the buckle switch terminals with a multimeter and compare to the manufacturer's specification for latched and unlatched states.
Check for continuity and short-to-ground or short-to-voltage on the wiring between the buckle switch and the BCM, flexing the harness to reveal intermittent faults.
If the switch and wiring test good, substitute a known-good buckle switch or simulate the correct signal at the BCM connector to isolate the fault.
Clear the code and verify repair by cycling the ignition and confirming the live data and warning light behave correctly.
If all external circuits are good, follow the manufacturer's diagnostic flow for BCM replacement or reprogramming as a last resort.

Why the buckle switch code misleads

A passenger seat belt buckle switch that tests fine on a bench can still set B0154 intermittently due to a worn internal contact that only fails at certain temperatures or vibration levels.
The BCM often shares the buckle switch ground with other seat-mounted sensors, so a bad ground can set this code along with unrelated seat-related codes.
Some vehicles use a resistor ladder in the buckle switch, and a small change in resistance from corrosion can push the signal out of range without a complete open or short.
After a collision repair, the buckle switch may be replaced with a used part that has a different resistance range, causing a persistent B0154 even though the switch functions.
The code can be set by a low battery or voltage spike that corrupts the BCM's learned buckle switch values, so clearing the code after a battery service may resolve it without parts.

Can I keep driving with B0154?

The vehicle is generally safe to drive because the seat belt still latches mechanically, but the passenger airbag may not deploy correctly in a crash if the buckle status is wrong. Avoid carrying passengers in the front seat until the fault is repaired, and have the system diagnosed promptly.

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.