B0206 – Occupant Presence System Fault

System: Body | Standard: ISO/SAE Controlled | Fault type: General

Definition source: SAE J2012/J2012DA (industry standard)

DTC B0206 indicates an Occupant Presence System Fault within the vehicle’s body system. The occupant presence system is part of the passenger-side occupant detection strategy used to help the vehicle determine whether a seat is occupied and how related safety functions should behave. When B0206 sets, it means a control module has detected that the occupant presence system is not operating as expected, but it does not, by itself, confirm which component has failed or whether an occupant is truly present. DTC behavior, enabling conditions, and the exact inputs monitored can vary by vehicle, so always verify the diagnostic approach, connector views, and test specifications using the correct service information for the vehicle you are working on.

What Does B0206 Mean?

B0206 means the vehicle has detected an Occupant Presence System Fault. In practical diagnostic terms, a module responsible for monitoring passenger-seat occupant detection has identified a fault condition in that system and stored B0206 to flag the issue. SAE J2012 defines how DTCs are structured and categorized, but the code’s meaning here is strictly the official definition: the occupant presence system has faulted. The code alone does not specify whether the issue is a sensor, wiring, power/ground, calibration, or a module-side problem; those details must be determined through testing and by confirming how the system is designed on the specific vehicle.

Quick Reference

• Subsystem: Occupant presence system (passenger seat occupant detection inputs and related module processing).
• Common triggers: Unstable or implausible occupant detection signals, communication/initialization issues, or a detected system self-check failure (varies by vehicle).
• Likely root-cause buckets: Wiring/connector concerns, occupant presence sensor/mat assembly, power/ground problems, module or configuration/calibration issues.
• Severity: Safety-related; may affect passenger-side restraint/indicator behavior, so treat as important even if drivability feels normal.
• First checks: Scan for related body/SRS codes, verify battery/charging health, inspect seat-area connectors and harness routing, confirm no obvious connection or damage issues.
• Common mistakes: Replacing the sensor/mat without verifying power/ground integrity, connector fit, harness damage, or required setup/calibration after repairs.

Theory of Operation

The occupant presence system typically uses a passenger-seat sensing element (design varies by vehicle) and related electronics to provide an occupant-status signal to a controlling module. The module interprets this input to determine whether the system is functioning and whether the reported occupant state is credible. Depending on platform, the occupant presence information may be used by body or safety-related control logic and may also be shared over the vehicle network.

B0206 can set when the module detects that the occupant presence system is not operating correctly during self-tests, initialization, or normal operation. Fault detection may involve checking for signal stability, expected transitions, wiring integrity indicators, or internal consistency checks. Because the monitored inputs and pass/fail criteria vary by vehicle, service information should be used to identify the exact monitored circuits, connectors, and required setup steps.

Symptoms

• Warning lamp: A safety or body warning indicator may illuminate or a related message may appear, depending on vehicle strategy.
• Status display: Passenger-side occupant/seat status indication may behave unexpectedly or not match actual seat conditions (varies by vehicle).
• Intermittent behavior: The fault may come and go with seat movement, temperature changes, or vibration due to marginal connections.
• Stored codes: Additional related diagnostic codes may be stored in body or safety-related modules that share occupant presence information.
• System disablement: The vehicle may limit or default certain passenger-side safety functions as a precaution when occupant status is unreliable.
• No drivability change: Engine performance and general driving feel are often unaffected even though the fault is safety-relevant.

Common Causes

• Loose, damaged, or contaminated connectors in the occupant presence sensor mat/cushion harness or at the control module
• Harness damage under or around the seat (pinched wiring, abrasion, stretched conductors from seat movement)
• Poor pin fit, partial terminal push-out, or corrosion causing intermittent contact
• Open circuit or high resistance in power, ground, or signal circuits feeding the occupant presence system
• Short-to-ground or short-to-power affecting the occupant presence sensor signal or its reference circuits
• Occupant presence sensor/mat fault (internal break, degraded sensing element, or failed integral electronics where used)
• Improper repairs or modifications (non-approved splices, incorrect terminals, or routing that allows repeated flexing)
• Control module fault or configuration/calibration issue (varies by vehicle) that prevents correct interpretation of the sensor signal

Diagnosis Steps

Tools typically needed include a scan tool capable of reading body DTCs and live data, a digital multimeter, and basic back-probing tools. Service information is required for connector views, pinouts, and the correct testing method for the occupant presence system (some designs restrict probing or require specific procedures). A low-amp test light and wiring repair tools may also be helpful.

1. Confirm the DTC is current. Record all stored and pending body DTCs and freeze-frame/event data (if available). Note any related restraint/airbag or seat-related codes, since they may share power, ground, or network paths.
2. Check scan tool data and indicators. Review occupant presence system status and any seat occupancy/enable parameters (naming varies by vehicle). Compare what the module reports with actual seat conditions without forcing or stressing the seat cushion.
3. Clear codes and perform a controlled recheck. Clear the DTC and run the relevant monitor or perform a short road test while observing live data. If B0206 resets immediately, treat it as a hard fault; if it returns intermittently, prioritize connector/harness movement and contact issues.
4. Perform a visual inspection under and around the seat. Look for pinched wiring, damaged conduit, pulled connectors, signs of contamination, or evidence that the harness has been rubbing on seat tracks. Ensure harness routing allows full seat travel without tension.
5. Connector inspection and pin fit check. With power off as directed by service information, disconnect the occupant presence sensor connector(s) and module-side connector(s) involved. Inspect for bent pins, spread terminals, partial push-out, moisture/corrosion, and improper repairs. Verify terminal tension/retention using appropriate methods (do not force oversized probes).
6. Wiggle test with live data logging. Reconnect components as required, then log live data and DTC status while gently wiggling the harness, connectors, and seat-to-floor transitions. Move the seat through its travel range (as safely allowed) and watch for dropouts, sudden state changes, or DTC reset.
7. Power and ground integrity checks. Using the wiring diagram, verify the presence and stability of required feeds and grounds for the occupant presence system and any related module. Use voltage-drop testing on power and ground paths under load where possible; excessive drop indicates high resistance in wiring, splices, or terminals.
8. Signal circuit checks for opens/shorts. With connectors disconnected as appropriate and following service procedures, check the relevant signal/reference circuits for continuity and for shorts to ground or power. Pay close attention to sections of harness that flex with seat movement or pass near metal edges.
9. Subsystem isolation (varies by vehicle). If the design allows, isolate whether the fault follows the sensor/mat side or remains with the module/harness side by testing at different points in the circuit per service information. Do not substitute parts or jump circuits unless the OEM procedure explicitly permits it.
10. Evaluate module-side causes only after circuit checks pass. If wiring, connectors, power/ground integrity, and sensor-side checks are all verified good, follow service information for any required setup, calibration/zeroing, or configuration verification. Only then consider a control module fault as a remaining possibility.

Professional tip: Many occupant presence faults are intermittent and related to seat movement. The most productive approach is to combine a careful under-seat harness/connector inspection with live-data logging during a gentle wiggle test and full seat travel check. If the status flickers or the code resets during movement, focus on terminal tension, pin fit, and harness strain points before considering sensor or module replacement.

Possible Fixes & Repair Costs

Repair costs for B0206 vary widely because the fault can be caused by anything from a simple connection issue to a sensor or module problem. The total depends on correct diagnosis, parts required, labor time to access seat components, and whether calibration is needed afterward.

• Repair wiring faults by fixing opens/shorts, damaged insulation, or pinched sections in the occupant presence system harness (verify the fault is eliminated after repair).
• Clean and secure connectors by addressing loose seating, corrosion, contamination, or poor pin fit at the sensor, seat harness junctions, and control module connections.
• Restore power/ground integrity by repairing feed/ground circuits and correcting excessive voltage drop found during loaded testing.
• Replace the occupant presence sensor/mat only after confirming its signal and circuit integrity do not meet expected behavior per service information.
• Perform required calibration/setup if the platform requires an occupant presence system relearn, zeroing procedure, or configuration after component replacement.
• Repair or replace affected seat components (as applicable) if movement or mechanical interference is verified to be damaging wiring or compromising sensor operation.
• Address control module issues only after all external circuit/sensor checks pass; update/reflash or replace the module as directed by service information.

Can I Still Drive With B0206?

You may be able to drive with B0206, but treat it as a safety-related warning because an occupant presence system fault can affect how occupant detection is interpreted by vehicle safety functions. If any safety indicator is on, or if you have warnings related to restraint/airbag operation, avoid carrying passengers in the affected seat and have the system diagnosed promptly. If the vehicle displays additional critical warnings or abnormal behavior in other systems, do not drive until it is inspected.

What Happens If You Ignore B0206?

Ignoring B0206 can leave the occupant presence system in a faulted state, which may cause the vehicle to disable certain functions or use default strategies that may not reflect actual seat occupancy. The warning may remain on, the fault may become intermittent and harder to pinpoint, and repeated seat movement can worsen wiring/connector damage, increasing repair complexity.

Last updated: March 14, 2026

Vehicles Commonly Affected by B0206

• Passenger vehicles equipped with an occupant presence detection system in the front passenger seat.
• Vehicles with seat-mounted sensors integrated into cushions, seat frames, or seat trim assemblies.
• Vehicles with under-seat harnessing exposed to frequent seat movement from fore/aft and height adjustments.
• Vehicles with removable or serviced seats where connectors may be disturbed during interior repairs.
• Vehicles used in high-debris environments where contamination can enter under-seat connectors.
• Vehicles with frequent passenger seat use increasing cycles on connectors and harness routing points.
• Vehicles with prior electrical work near the seat area, including accessory wiring routed under seats.
• Vehicles with water intrusion history affecting cabin floor areas and low-mounted connectors.