AU
B1630-00

DTC B1630-00 indicates the SRS (Supplemental Restraint System) control module detects an open circuit or high resistance in the right front seat side airbag module circuit — Atto 8

Safety System

DTC B1630-00 indicates the SRS (Supplemental Restraint System) control module detects an open circuit or high resistance in the right front seat side airbag module circuit.

The resistance exceeds the calibrated range (typically >10Ω).

This represents a hard fault in the airbag system; the right front seat side airbag fails to deploy during a side-impact collision.

The system enters fail-safe mode and continuously illuminates the instrument cluster airbag warning light.

Potential causes include an open wiring circuit, a disconnected connector, an open airbag squib, or excessive contact resistance.

4
Cases Logged
5
Causes
Likely Causes — Atto 8
  • 1Loose or completely disconnected SRS-specific yellow connector under the seat: Vibration from moving the seat forward and backward, or passenger foot impacts, loosens the under-seat airbag wiring harness connector (usually equipped with a shorting bar protection mechanism).
  • 2Wiring harness wear and breakage at the seat slide rail: During fore-and-aft seat adjustment, the side airbag wiring harness (transition section from the body floor harness to the seat) bends repeatedly at the slide rail. This causes the internal copper wires to fatigue and break while the outer insulation remains intact.
  • 3Internal open circuit in the airbag module: Side airbag assembly squib open circuit or damaged clock spring, typically resulting from component aging or failure to replace the airbag after a previous accidental deployment.
  • 4Connector terminal oxidation or poor contact: Vehicle wading or a humid environment oxidizes the under-seat plug terminals, creating high contact resistance (>2Ω) that the ECU identifies as disconnected.
  • 5Not reset after previous repair: After replacing the seat cover, repairing the seat heating, or removing and installing interior trim, the technician failed to reconnect the airbag connector or release the shorting bar.
What To Do
  • 1
    Safe power-down: Switch off the ignition, disconnect the 12V battery negative terminal, and wait at least 90 seconds (to fully discharge the SRS capacitor). Do not operate any electrical equipment during this time.
  • 2
    Visual inspection and location: Move the right front seat to the fully forward position. Inspect the yellow SRS connector under the seat (usually located on the inner or rear side of the seat, featuring a double-locking mechanism). Confirm the connector seats fully with an audible locking 'click', and verify the shorting bar has sprung open.
  • 3
    Resistance measurement verification: Use a multimeter to measure the airbag circuit resistance. Disconnect the airbag connector. Measure the wiring harness resistance at the ECU end (must be infinite to rule out a short to ground). Measure the module resistance on the airbag side (standard value: 2.0-3.0 Ω; if >10 Ω, replace the airbag module).
  • 4
    Harness continuity check: Inspect the wiring harness corrugated conduit from the seat to the body floor, focusing on the bend at the seat slide rail. Remove the tape and check for broken wires, exposed copper strands, or pinch marks. Repair the harness if necessary and re-wrap it.
  • 5
    Clean and secure: If the connector shows oxidation or corrosion, clean the terminals with electrical contact cleaner and apply conductive grease. Reconnect the connector and secure the wiring harness to the seat frame with cable ties to prevent interference with moving parts.
  • 6
    System reset test: Reconnect the battery, turn the ignition switch to the ON position, and clear the fault code using the diagnostic tool. Verify the instrument cluster SRS warning light turns off after 6 seconds. Read the data stream to confirm the right front side airbag status is 'normal' (resistance value within the normal range).
  • 7
    Function verification: Use the diagnostic tool to perform the 'Airbag System Self-check' or 'Crash Sensor Test'. Verify no current fault codes exist. Move the seat forward and backward to confirm the fault does not recur.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Frequent seat adjustment caused the connector to work loose

✓
A 2018 BYD Qin EV450 came in with the airbag warning light on constantly. Retrieved DTC B1630-00. Found the yellow SRS connector beneath the right front seat had loosened about 2mm, and the locking click was not fully heard. The cause: the owner frequently allowed rear passengers to adjust the seat, gradually working the connector loose. Repair: reconnected the connector, confirmed the double-locking mechanism was fully seated, and secured the wiring harness to the seat spring with a cable tie to prevent movement. Cleared the fault code; normal operation returned.
BYD DTC AI AnalysisFrom Chinese market (translated)

Seat rail chafed wiring harness - open circuit

✓
A 2019 BYD E1 with 80,000 km on the odometer displayed an airbag fault on the instrument cluster. The scan tool showed DTC B1630-00. Disassembly and inspection revealed the right front seat side airbag harness, at the bend behind the slide rail, had its outer insulation intact while both internal copper wires were completely broken. The cause was fatigue failure from the harness rubbing against the metal slide rail edge during repeated fore-aft seat movement. Repair: Replaced the seat wiring harness assembly (0.5mm² cross-section or larger, high-temperature rated), rerouted the harness to add slack, and fitted a rubber protective sleeve at the bend.
BYD DTC AI AnalysisFrom Chinese market (translated)

Connector oxidised after water ingress, causing poor contact

✓
A 2017 Qin 100 suffered water ingress in the right front carpet due to a blocked sunroof drain tube, causing the airbag warning light to come on. Logged DTC B1630-00. Inspection found significant water staining inside the connector beneath the seat, green oxide on the copper terminals, and contact resistance of 15 Ω (should be <1 Ω). Repair: disconnected the connector, cleaned the terminals with anhydrous alcohol, dried them, applied electrical contact protectant, and replaced the connector housing if needed. Also cleared the sunroof drain tube and air-dried the carpet to prevent the carpet from getting damp again.
BYD DTC AI AnalysisFrom Chinese market (translated)

Did not reconnect the airbag connector after replacing the seat cover

✓
A 2018 Qin EV450 developed an airbag warning light after a detailing shop reupholstered the seats in leather. Scanned code B1630-00. Inspection found the right front seat side airbag connector fully disconnected, with the shorting bar in the closed position (used during repairs to prevent accidental deployment from static electricity). The shop admitted they disconnected the plug during seat removal and refitting and forgot to reconnect it. Solution: Reconnected the plug and confirmed it locked securely. Advised the owner that SRS repairs require qualified technicians.
Other Atto 8 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. Sources: [1]