AU
B1610

DTC B1610 indicates the Airbag Control Unit (ACU) detects an open circuit in the front passenger airbag squib circuit — Seal U

Safety System

DTC B1610 indicates the Airbag Control Unit (ACU) detects an open circuit in the front passenger airbag squib circuit.

Resistance falls outside the normal range (normal: approximately 1.5-3.0Ω; fault: typically >10Ω or infinite).

This indicates a physical break in the circuit between the ACU and the front passenger airbag module (located inside the right side of the dashboard).

Possible causes include a loose wiring harness connector, an open circuit in the airbag module inflator, wiring harness wear or breakage, or a clock spring fault (if applicable).

This fault prevents the front passenger airbag from deploying during a collision, severely compromising occupant protection.

Other vehicle systems continue to operate normally.

4
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Front passenger airbag wiring harness connector loose or disconnected: Located inside the right side of the dashboard or at the floor harness joint. Previous repairs failing to fully seat the connector or vehicle vibration during driving may cause it to loosen.
  • 2Airbag module internal open circuit: Internal open circuit in the gas generator igniter, typically due to manufacturing defects or long-term environmental exposure.
  • 3Wiring harness worn or broken: Front passenger-side floor wiring harness worn from long-term bending near the seat slide rail, or a metal edge cut the dashboard wiring harness.
  • 4Connector pin oxidation or pin back-out: Moisture ingress causes pin corrosion, or poor terminal retention causes pins to back out, resulting in poor contact.
  • 5Airbag Control Unit (ACU) internal fault: ACU internal monitoring circuit fault causing false reports, or dry solder joint at an internal connection point (less common, but rule out).
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal and wait at least 3 minutes to fully discharge the SRS system capacitor and prevent accidental airbag deployment.
  • 2
    Preliminary check: Use the diagnostic tool to read and confirm DTC B1610 is Active. Check if the airbag warning lamp remains illuminated. Record freeze frame data.
  • 3
    Visual inspection: Remove the passenger-side dashboard side trim panel. Inspect the airbag module wiring harness connector (usually a yellow plug) for a secure connection. Verify the connector locking tab is intact.
  • 4
    Resistance measurement: Use a digital multimeter to measure the airbag circuit resistance (requires a dedicated airbag load simulator or a multimeter test current <1mA). The normal value is 1.5-3.0 Ω. A reading of OL or infinity confirms an open circuit.
  • 5
    Fault isolation: Disconnect the airbag module connector and measure resistance on the wiring harness side and the module side separately. If the module side has an open circuit, replace the airbag module. If the wiring harness side has an open circuit, check floor wiring harness continuity, focusing on the bent section under the seat.
  • 6
    Wiring harness repair: If damaged, repair the wiring harness using high-temperature wire of the same specification (usually 0.5mm² twisted pair). Solder the joints and apply double insulation. Do not use basic crimp connectors.
  • 7
    Verification test: Reconnect all components and the battery. Clear the fault code using the diagnostic tool. Cycle the ignition switch. Verify B1610 does not return and the airbag warning light turns off normally.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Yuan EV: Worn wiring harness under passenger seat causing intermittent open circuit

✓
The vehicle is a 2019 BYD Yuan EV535 with 42,000 km. The instrument cluster intermittently displayed the airbag warning light. The scan tool retrieved stored DTC B1610. Inspection found the front passenger seat rail pinched the floor wiring harness during fore-aft adjustment, cracking the copper conductor inside the airbag circuit wire while the insulation stayed intact, creating an intermittent open circuit. Remedy: replaced the damaged harness section (approx. 30 cm) and repositioned the harness retaining clips away from the seat rail travel path. Fault resolved.
BYD DTC AI AnalysisFrom Chinese market (translated)

Loose front passenger airbag connector on Tang DM caused high resistance.

✓
2021 Tang DM. Customer reported the airbag light constantly on. Retrieved active fault code B1610. Removed and inspected the passenger airbag module on the right side of the dashboard, finding the yellow 2-pin connector not fully seated and locked (lock tab disengaged), likely from accidental contact during previous glove box removal/installation. Reconnected the connector and confirmed the lock tab engaged. Measured resistance restored to 2.1Ω. Cleared the fault code and the system returned to normal.
BYD DTC AI AnalysisFrom Chinese market (translated)

Qin Pro Airbag Module Internal Open Circuit Replacement Case

✓
2020 BYD Qin petrol model. Airbag warning light came on after accident repairs. Diagnostic scan revealed DTC B1610. Inspected wiring harness connector and found it in good condition. Measured resistance at harness side: normal at approximately 0.5 Ω (wire resistance). However, measured infinite resistance at airbag module connector. Determined internal open circuit in passenger airbag gas generator. Installed new passenger airbag module (part number must match VIN), performed programming and configuration, and resolved the fault. Disassembly of the old component revealed moisture damage to the internal igniter pellet, causing corrosion and an open circuit.
BYD DTC AI AnalysisFrom Chinese market (translated)

Song MAX Dashboard Wiring Harness Pin Back-Out Fault

✓
2019 Song MAX. Airbag warning light came on after driving through water. DTC B1610. Inspection found traces of water inside the passenger airbag harness connector (right side of dashboard frame). One terminal (typically the negative wire) had corroded, causing the retention clip to fail and the terminal to back out, resulting in poor contact. Repair: Cleaned connector, replaced backed-out terminal with an identical TE Connectivity terminal, applied conductive protective grease. Resistance stable after repair.
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. Sources: [1]