AU
B16F200

DTC B16F200 indicates the airbag control unit (SRS ECU) detects abnormal configuration parameters for the right rear side impact sensor (C-pillar/rear quarter panel) — Seal U

Safety System

DTC B16F200 indicates the airbag control unit (SRS ECU) detects abnormal configuration parameters for the right rear side impact sensor (C-pillar/rear quarter panel).

This is a configuration fault, not a hardware failure.

The sensor ID, installation position parameters, sensitivity calibration data, or hardware identification code stored in the SRS ECU do not match the installed physical sensor.

While the sensor still communicates, the ECU cannot correctly interpret its crash signal threshold, potentially causing unintended deployment or failure of the side airbags or curtain airbags.

Common triggers include: failing to perform online configuration after replacing the sensor during collision repair, using non-OEM parts causing a hardware ID mismatch, losing configuration data after an SRS software update, or interrupting the programming process resulting in incomplete configuration.

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Cases Logged
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Causes
Likely Causes — Seal U
  • 1Configuration/calibration not performed after replacing the right rear crash sensor: Technician replaced the hardware only and did not use the VDS diagnostic tool to perform the 'Crash Sensor Configuration' or 'Coding' procedure, preventing the ECU from recognizing the new sensor's hardware ID.
  • 2Sensor hardware model mismatch: Installing a sensor with the wrong part number (e.g., fitting a low-spec sensor to a high-spec vehicle, or swapping left and right sensors) causes the SRS ECU to fail the hardware coding verification.
  • 3SRS control unit software fault: Corrupted configuration data in the control unit internal EEPROM, outdated software version incompatible with new sensors, or configuration area data errors caused by power loss during an upgrade.
  • 4Poor wiring harness contact causing configuration communication failure: The right rear sensor is behind the C-pillar trim panel. A loose harness connector, backed-out terminal pin, or oxidation prevents fully writing the configuration command to the sensor memory.
  • 5Safety system not fully reset after an accident: Although the sensor was replaced after a side impact, failing to perform "crash data clearing" and "system reconfiguration" on the SRS system causes the ECU to retain the old sensor's fault configuration record.
What To Do
  • 1
    Step 1: Use the BYD VDS diagnostic tool to access the SRS system. Read all fault codes, check for accompanying faults (such as B16F300 communication fault, U0141 lost communication with BCM, etc.), and record the freeze frame data (ambient voltage, temperature, mileage).
  • 2
    Step 2: Remove the right rear C-pillar trim panel. Visually inspect the right rear crash sensor for physical damage. Check the wiring harness connector (usually located above the rear sill beam or in the middle of the C-pillar) for a secure connection. Measure the connector terminal voltages (should have 12V constant power, ground, and CAN-H/CAN-L) and confirm no short or open circuits.
  • 3
    Step 3: Verify the sensor part number: Remove the sensor and check the label part number (e.g., BYD-XXX-SRS-RR). Check the EPC system to verify it is the correct part number for the current model year/VIN. Confirm no left/right or high/low-spec parts are mixed.
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    Step 4: Perform sensor configuration: Go to VDS → SRS system → Special Functions → 'Crash Sensor Configuration' or 'Coding', select 'Right Rear Sensor', enter the hardware code from the sensor label as prompted (or scan the barcode), execute the write operation, and verify the screen displays 'Configuration Successful'.
  • 5
    Step 5: SRS system calibration: Run the 'Crash Sensor Calibration' function to perform zero-point calibration and sensitivity learning on the right rear sensor to ensure the sensor correctly identifies the vehicle stationary-state reference value.
  • 6
    Step 6: Clear fault codes and perform self-check: Clear all SRS history fault codes, execute 'System Self-Test', and confirm B16F200 does not return. Read the live data stream to confirm the right rear sensor status is 'Normal' and the signal voltage is within the specified range (typically 2.5V±0.1V static).
  • 7
    Step 7: Function verification: Perform a simulated crash test (use the dedicated diagnostic tool function or lightly tap the vehicle body near the sensor, non-destructively). Confirm the SRS ECU correctly receives the acceleration signal change from the right rear sensor. Verify the instrument cluster airbag warning light turns off and triggers no further warnings.
Real-World Cases
BYD DTC AI Analysis

Sensor not configured after accident repair caused B16F200 on BYD Qin Pro DM

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Model: 2019 Qin Pro DM. Symptoms: After right-side accident repairs, the airbag warning light on the instrument cluster stayed on. VDS scan pulled code B16F200. Diagnosis: Inspection found the right rear quarter panel had been cut and replaced. The newly installed crash sensor was a genuine part, but its part number suffix did not match the vehicle configuration (a base-model sensor had been installed). Solution: Replaced the right rear crash sensor with the high-spec version (part number: BYD-3636600-C1), performed VDS online configuration and calibration. Fault resolved.
BYD DTC AI Analysis

E3 BEV SRS configuration data lost after software update

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Model: 2020 BYD E3. Symptom: After the dealership upgraded the SRS control unit software, the instrument cluster displayed an airbag fault. DTC B16F200 was stored. Diagnosis: An interruption during the upgrade corrupted the sensor configuration data in the EEPROM. Solution: Re-downloaded the correct software version, ran ‘SRS system reconfiguration’, then performed ID writing and position calibration individually for all four crash sensors (left-front, right-front, left-rear, right-rear). Cleared the fault codes, and the system returned to normal.
BYD DTC AI Analysis

Qin EV right rear sensor connector oxidised, causing intermittent configuration error

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Model: 2019 Qin EV. Symptom: Intermittent airbag warning light, frequently occurring during cold starts and clearing when warm. DTC: B16F200. Diagnosis: Measured the right rear sensor harness connector, found abnormal resistance at the CAN-L terminal (oxidation caused increased contact resistance) and incomplete configuration data. Solution: Cleaned the harness connector terminals, applied conductive grease, reconnected, and performed sensor reconfiguration. The fault has not recurred.
BYD DTC AI Analysis

Replaced rear quarter panel assembly on E2 without running the configuration procedure.

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Model: 2019 BYD E2. Symptom: After rear-end collision repairs, the owner collected the vehicle and found the airbag light on; the repair shop could not clear it. Diagnosis: When replacing the rear quarter panel assembly, the technician also replaced the built-in right rear impact sensor but did not configure it. Solution: Used VDS to access the special functions menu, selected 'Collision Sensor Replacement', completed the pairing of the new sensor with the SRS ECU as prompted, cleared the DTCs, and the system returned to normal.
Other Seal U Fault Codes
B1108For the BYD Song MAX (2017–2019), DTC B1108 indicates a short circuit in the PM2.5 air quality detection module (dust sensor) or its wiring harness. The sensor uses laser scattering to detect in-cabin and outside PM2.5 concentrations and transmits data to the HVAC ECU via the LIN bus or an analog signal. Short circuit conditions include: 1) Sensor power supply wire (+5V/+12V) shorted to ground 2) Signal wire shorted to power or ground 3) Short circuit in the sensor's internal photoelectric detection circuit This fault prevents the automatic climate control from switching between fresh air and recirculation based on air quality. The system enters fail-safe mode (typically forced recirculation). Severe short-circuit current can destroy the HVAC ECU sampling circuit. The system classifies this as a Level 3 severe fault and restricts vehicle operation to prevent electrical fires or controller damage. For other BYD models (such as the Qin EV, E5, and Song DM), B1108 indicates a driver-side sunload sensor fault, reflecting differences in DTC definitions across models.B110811This DTC indicates a short circuit in the air conditioning system PM2.5 air quality sensor (rapid detector). Specifically, abnormal continuity exists between the sensor power supply circuit or signal output circuit and body ground or battery positive. This causes the control module (ACU/air conditioning controller) to detect abnormal current or a voltage signal outside the valid range (typically 0V or supply voltage). The PM2.5 sensor monitors internal and external particulate concentrations, providing the data the automatic air conditioning system uses to switch between fresh air and recirculation modes. A short circuit disables the air quality monitoring function. This fault may force the air conditioning system into recirculation protection mode and trigger related thermal management system faults, as the air conditioning system acts as a key actuator in vehicle thermal management. In severe cases, the short circuit current can damage the internal sampling circuit of the air conditioning controller or overheat the wiring harness.B1109DTC B1109 indicates an open circuit in the communication line between the air conditioning system PM2.5 air quality sensor (dust concentration sensor) and the air conditioning control unit (AC ECU), or an open circuit within the sensor internal circuitry. Typically located in the air conditioning intake duct, this sensor monitors real-time PM2.5 particle concentration inside and outside the vehicle. It provides data to the automatic air conditioning system for intelligent switching between fresh air and recirculation modes and for controlling the air purification device. During an open circuit fault, the AC ECU cannot receive the air quality signal, triggering the system fail-safe mode. Symptoms typically include failure of the automatic recirculation function, abnormal air purification indicator light operation, or abnormal air quality data displayed on the air conditioning panel. Severe cases may compromise the cabin environment control strategy, but do not directly affect vehicle driving safety.B110913DTC B110913 indicates an open signal circuit for the PM2.5 rapid detector (in-cabin air quality sensor). This sensor typically mounts inside the air conditioning system intake duct. It monitors in-cabin PM2.5 concentration in real time and provides data to the automatic air conditioning system for intelligent control of the air purification function. The BYD diagnostic protocol uses sub-code '13' to specifically indicate an open signal circuit. Although this fault theoretically affects a comfort feature, BYD Qin series vehicles classify it as a Level 3 (severe) fault. This classification occurs because the air conditioning system interacts with the battery thermal management system (e.g., monitoring battery cooling intake air quality). The fault can disable the automatic air conditioning mode and prevent the air purification function from operating. In extreme cases, it affects the battery compartment intake air quality assessment, triggering the 'repair immediately' strategy.B110AThis DTC indicates interrupted CAN bus communication or abnormal data between the air conditioning control unit (ACU) and the PM2.5 air quality sensor. The PM2.5 sensor monitors particulate concentration inside and outside the vehicle and provides the basis for purification control in the automatic air conditioning system. The ACU triggers this fault if it fails to receive a valid CAN message from the sensor within the specified period (usually 100-500 ms), if message verification fails, or if the signal frame times out. Although this fault does not affect vehicle driving safety, it disables the automatic air purification function. The air conditioning system cannot automatically switch between recirculation and fresh air modes or activate the air purification mode based on air quality. A persistent fault may restrict the thermal management strategy.
Data confidence: Official This information is for reference only. Always consult a qualified technician for diagnosis and repair. Do not attempt high-voltage system repairs yourself.