AU
B17A200

This DTC indicates that the airbag control unit (SRS ECU) has detected a collision event meeting the deployment threshold, permanently written the crash data to the ECU internal non-volatile memory (NVRAM), and activated the crash lock protection mechanism — Seal 6 EV

Safety System

This DTC indicates that the airbag control unit (SRS ECU) has detected a collision event meeting the deployment threshold, permanently written the crash data to the ECU internal non-volatile memory (NVRAM), and activated the crash lock protection mechanism.

In this state, the SRS system enters safe mode, disables further airbag deployment to prevent secondary injury, and illuminates the warning lamp continuously.

A genuine collision event (deployed or recorded without deployment) can trigger this lock.

Crash sensor faults, wiring harness short/open circuits, ECU algorithm miscalculations, or power supply system anomalies can also generate a false record.

Once locked, standard DTC clearing cannot erase the code.

Reset the data using dedicated diagnostic equipment, or replace the ECU.

The B17A200 fault code on the Seal 6 EV indicates the SRS airbag ECU has recorded crash data and activated crash lock protection. Severity is medium because the airbag system enters safe mode and may not deploy again until repaired. Common causes include a real collision event or faulty crash sensors/wiring sending abnormal acceleration signals. Visit an authorised dealer to reset crash data with dedicated equipment or replace the ECU. Typical repair cost data is available.
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Cases Logged
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Causes
Likely Causes — Seal 6 EV
  • 1The vehicle experienced an actual collision (regardless of airbag deployment); the SRS ECU recorded longitudinal/lateral acceleration sensor data and locked the system.
  • 2Internal short circuit, open circuit, or signal drift in the front impact sensor, side impact sensor, or central sensor causes the ECU to receive an abnormal acceleration signal.
  • 3Damaged SRS ECU internal memory chip, software bug, or power supply fluctuations (such as voltage spikes when jump-starting a discharged battery) causing incorrect writes to the data area.
  • 4Handling the airbag wiring harness during repairs without disconnecting the battery, or water ingress or oxidation in the yellow connector (dedicated to the airbag) causing abnormal resistance that the system falsely identifies as a collision.
  • 5Failure to replace the locked SRS ECU during accident repairs (on some BYD models, the ECU is a single-use component requiring replacement after recording a collision).
What To Do
  • 1
    Use the BYD dedicated diagnostic tool (VDS2000/3000 or ED400) to access the SRS system. Read the complete fault codes, freeze frame data, and crash record. Confirm the trigger time, triggered sensor location, and collision severity value (Delta-V).
  • 2
    Check the vehicle repair history against the freeze frame time. Visually inspect the front and rear longitudinal rails, crash beams, B-pillars, and sill panels for signs of sheet metal repair to confirm a genuine collision or a false alarm.
  • 3
    Disconnect the battery negative terminal for 3 minutes. Check all yellow SRS wiring harness connectors (especially the floor harness and sensor connectors) for water ingress or oxidation. Measure the crash sensor resistance (normal: 2.0-3.0 kΩ; abnormal: short circuit <1 kΩ or open circuit >10 kΩ).
  • 4
    If diagnosing a false alarm with no hardware damage: Use the diagnostic tool to perform the 'Crash Data Clear' function. Enter the BYD manufacturer-authorized password. If the ECU does not support clearing or clearing fails, replace the SRS ECU with a new unit (part number must match vehicle configuration).
  • 5
    If an actual collision occurred: Replace all deployed airbag modules, seat belt pretensioners, and crash sensors, and install a new SRS ECU (do not reuse a locked ECU).
  • 6
    After replacing the hardware, perform ECU coding, sensor calibration, and a system self-check. Conduct a road test to confirm DTC B17A200 does not return and the airbag warning light is off.
Real-World Cases
BYD DTC AI Analysis

BYD Qin Pro DM: SRS light stays on after accident repair

✓
2019 Qin Pro DM, minor front-end collision (bumper only, airbags did not deploy). After an external workshop replaced the bumper, the airbag warning light stayed on. VDS showed B17A200 Crash Record Locked; freeze frame indicated collision intensity of -1.2g (minor collision threshold). The shop had ignored the SRS system. Since the airbags never deployed, cleared the crash data using the manufacturer-authorized password, completed sensor calibration, and resolved the fault—avoiding replacement of the expensive ECU.
BYD DTC AI Analysis

Water ingress caused sensor short circuit and false locking.

✓
2018 BYD Qin Pro petrol. After driving in heavy rain, the instrument cluster showed an airbag fault. The scan tool retrieved DTCs B17A200 and B17A111 (left front impact sensor fault). Inspection found water ingress and oxidation in the left front rail impact sensor connector, with resistance at only 0.3kΩ (severe short). This caused the ECU to misdetect a frontal collision and lock the collision record. Replaced the left front impact sensor, cleaned the wiring harness connector, and cleared the collision record using the scan tool. System returned to normal.
BYD DTC AI Analysis

Collision record locked after battery replacement

✓
A 2019 Qin PRO DM displayed an airbag warning light at startup after technicians replaced the battery at a dealership. Scanning revealed DTC B17A200 with no other codes. The technician failed to disconnect the SRS power supply before removing the old battery. Voltage fluctuations during reconnection caused the ECU to log a false trigger. No collision damage was present. Technicians performed an ECU Reset via VDS and cleared the codes to resolve the issue—a typical software fault from power interference.
BYD DTC AI Analysis

SRS ECU internal damage; replacement required

✓
2018 Qin Pro DM, no accident history. SRS warning light suddenly lit. Scan tool showed DTC B17A200 and would not clear. Freeze frame data showed corruption (timestamp 1970, impact values abnormal). All sensors and wiring harnesses tested normal. Diagnosed as ECU internal storage chip failure. Replaced SRS ECU with new unit (Part No. SC-3638100). Completed online programming, coding and sensor calibration. Fault resolved. Old ECU analysis: Physical damage to internal Flash memory caused erroneous crash flag writing.
Other Seal 6 EV 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.B1737DTC B1737 indicates the Supplemental Restraint System (SRS) detected abnormal continuity between the right middle-row side airbag squib circuit (typically the second-row right seat side airbag or right curtain airbag) and the vehicle power supply (B+, battery positive). The SRS ECU monitors the airbag inflator resistance via an internal current source (normal resistance: 2.0–3.0 Ω). If the ECU detects the voltage across the inflator circuit remaining close to battery voltage (>5 V and approaching 12 V) instead of the expected low potential or floating state, it identifies a short to power. This fault prevents the airbag from deploying normally during a collision because the short circuit bypasses the firing current. In extreme cases, abnormal current can cause unintended deployment, posing a severe safety hazard.B173BDTC B173B indicates an abnormal electric A/C compressor speed feedback signal or a communication fault between the compressor controller and the motor. In BYD new energy models (e.g., Tang, Song, Qin, and Yuan series), this DTC belongs to the HVAC subsystem within the Body Control system and specifically involves the electric compressor closed-loop control circuit. The ECU sets this DTC when the compressor controller (IPM) fails to receive a valid pulse signal from the Hall speed sensor for more than 3 continuous seconds, or when the deviation between the detected actual speed and the target commanded speed exceeds the calibrated threshold (typically >500 rpm). This fault forces the A/C system into fail-safe mode and stops compressor operation. Symptoms include a complete lack of cooling, intermittent cooling, or a sharp decrease in cooling performance. The instrument cluster A/C warning lamp may also illuminate. Prolonged operation with this fault can degrade high-voltage system insulation or cause controller overcurrent damage.
Common problems reported for Seal 6 EV →Seal 6 EV overview →
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.