AU
B160B1A

DTC B160B1A indicates the Driver Airbag (DAB) deployment circuit resistance falls below the normal threshold set by the SRS ECU (typically 2 — Seal U

Safety System

DTC B160B1A indicates the Driver Airbag (DAB) deployment circuit resistance falls below the normal threshold set by the SRS ECU (typically 2.0-3.0Ω; values below 1.0Ω trigger this fault).

This constitutes a Supplemental Restraint System (SRS) hard-wire fault.

The ECU detects an abnormally low-resistance path in the deployment circuit.

Potential causes include a wiring short to ground, an internal short in the clock spring, an internal short in the airbag module, or a short between connectors.

This fault forces the airbag system into fail-safe mode and continuously illuminates the instrument cluster airbag warning light.

In extreme cases, the airbag may fail to deploy during a collision because the ECU misinterprets the condition as a short circuit and disables the deployment circuit.

In very rare cases, wiring interference creates a risk of unintended deployment.

5
Cases Logged
5
Causes
Likely Causes — Seal U
  • 1Internal short circuit in the clock spring (spiral cable): Frequent steering wheel rotation breaks the internal flat cable or wears the insulation layer, causing the ignition wire to short to ground or power.
  • 2Airbag wiring harness short to ground: The wiring harness below the steering wheel chafes inside the steering column tube, or a metal edge cuts the wiring harness inside the dashboard, causing the ignition circuit wire to short to body ground.
  • 3Airbag connector water ingress and corrosion: Poor sealing of the driver-side airbag connector (usually located under the steering wheel or on the back of the airbag module) allows water ingress after washing the vehicle or wading, causing a short circuit between pins.
  • 4Airbag module internal short circuit: Damaged insulation on the gas generator igniter internal resistance wire or a manufacturing defect causes an abnormal drop in resistance.
  • 5SRS ECU internal detection circuit fault: A fault in the control unit internal sampling resistor or A/D conversion circuit causes a false low resistance reading (actual circuit is normal).
What To Do
  • 1
    Safety preparation: Disconnect the 12V battery negative terminal and wait at least 90 seconds to fully discharge the SRS capacitor and prevent accidental airbag deployment.
  • 2
    Visual inspection: Check the clock spring connector under the steering wheel and the yellow airbag module plug for looseness, water ingress, corrosion, or pin deformation.
  • 3
    Resistance measurement: Use a digital multimeter (resistance setting) to measure the resistance between the airbag module terminals. Normal resistance is 2.0-3.0Ω. A reading <1.0Ω or near 0Ω indicates a short circuit.
  • 4
    Sectional isolation check: Disconnect the clock spring from the airbag module. Measure the resistance upstream (ECU side) and downstream (airbag side) of the clock spring to determine whether the short circuit is in the ECU-to-clock-spring section, the clock spring itself, or the clock-spring-to-airbag section.
  • 5
    Wiring harness continuity test: Measure the ignition circuit wire resistance to ground. If <1MΩ, a short to ground exists. Inspect the circuit for wear points and repair the insulation.
  • 6
    Component replacement verification: If circuit measurements are normal, substitute a known-good clock spring or airbag module to check for an internal component short circuit.
  • 7
    System Reset and Test: After repair, reconnect the battery. Use a BYD VDS or X-431 diagnostic tool to clear the fault code. Perform an SRS system self-test. Confirm B160B1A does not return and the airbag warning light turns off.
Real-World Cases
BYD DTC AI AnalysisFrom Chinese market (translated)

Internal short in the Qin Pro DM clockspring caused abnormal resistance.

✓
A 2019 Qin Pro DM with 42,000 km on the odometer displayed “Check airbag system” on the instrument cluster. Retrieved DTC B160B1A. Disconnected the airbag module and measured its resistance as normal (2.3Ω), but the circuit from the clock spring to the ECU measured only 0.4Ω, indicating an internal short in the clock spring. Replaced the clock spring, clearing the fault. Disassembling the old clock spring revealed that the internal flat cable insulation had worn through from prolonged steering movement, exposing copper wires that contacted the metal housing.
BYD DTC AI AnalysisFrom Chinese market (translated)

Driver airbag connector corroded and shorted after water ingress

✓
2018 BYD Qin Pro petrol. Airbag warning light illuminated after the vehicle drove through water, logging DTC B160B1A. Inspection found obvious water stains inside the yellow airbag connector beneath the steering wheel, with pins oxidised and blackened. Ignition circuit resistance to ground measured only 0.2 Ω. After cleaning, drying and applying conductive anti-corrosion paste to the connector, resistance returned to normal. Root cause traced to an aged seal on the steering wheel trim panel, which allowed water to enter the connector during washing, causing a short circuit.
BYD DTC AI AnalysisFrom Chinese market (translated)

Aftermarket steering wheel pinched the wiring harness, causing a short circuit.

✓
A 2019 Qin Pro DM set DTC B160B1A one week after the owner installed a racing steering wheel. The technician found the original airbag harness was not correctly routed during the modification. The metal edge of the steering wheel hub pinched the harness, crushing the insulation and causing a short to ground. The technician repaired the damaged harness by replacing sections of wire and reinforcing the insulation, then refitted the original steering wheel assembly to clear the fault. Reminder: Always use a dedicated wiring harness adapter when modifying the steering wheel to avoid pinching the original harness.
BYD DTC AI AnalysisFrom Chinese market (translated)

Airbag module internal resistance low

✓
During pre-delivery inspection of a new 2018 Qin Pro, found DTC B160B1A. Ruled out wiring harness and clock spring faults, then directly measured the airbag module body resistance: 0.8Ω (below the normal 2.0Ω lower limit). Diagnosed an internal manufacturing defect in the gas generator causing low resistance. Replaced the driver-side airbag module (including gas generator) and cleared the fault. Component quality issue.
BYD DTC AI AnalysisFrom Chinese market (translated)

SRS ECU false alarm (software fault)

✓
A 2019 Qin Pro DM intermittently set code B160B1A. When the fault occurred, the circuit resistance measured normal (2.1Ω). The code could be cleared but randomly reappeared while driving. We checked the ECU power and earth—both normal. We determined the cause was either an internal sampling circuit fault in the SRS ECU or a software calibration issue. After replacing the SRS control unit and flashing the latest software, the fault was eliminated.
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]